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{{Infobox praseodymium}}
'''Praseodymium''' is a [[chemical element]]; it has [[Symbol (chemistry)|symbol]] '''Pr''' and the [[atomic number]] 59. It is the third member of the [[lanthanide]] series and is considered one of the [[rare-earth metal]]s. It is a soft, silvery, malleable and ductile [[metal]], valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in [[Native element mineral|native form]], and pure praseodymium metal slowly develops a green oxide coating when exposed to air.
Praseodymium always occurs naturally together with the other rare-earth metals. It is the sixth-most abundant rare-earth element and fourth-most abundant lanthanide, making up 9.1 [[parts per million]] of the Earth's crust, an abundance similar to that of [[boron]]. In 1841, Swedish chemist [[Carl Gustav Mosander]] extracted a rare-earth oxide residue he called [[didymium]] from a residue he called "lanthana", in turn separated from [[cerium]] salts. In 1885, the Austrian chemist [[Carl Auer von Welsbach]] separated didymium into two elements that gave salts of different colours, which he named praseodymium and [[neodymium]]. The name praseodymium comes from the Ancient Greek {{lang|grc|πράσινος}} ({{transl|grc|prasinos}}), meaning '[[leek]]-green', and {{lang|grc|δίδυμος}} ({{transl|grc|didymos}}) 'twin'.
Like most [[rare-earth element]]s, praseodymium most readily forms the +3 [[oxidation state]], which is the only stable state in [[aqueous solution]], although the +4 oxidation state is known in some solid compounds and, uniquely among the lanthanides, the +5 oxidation state is attainable in [[Matrix isolation|matrix-isolation conditions]]. The 0, +1, and +2 oxidation states are rarely found. Aqueous praseodymium ions are yellowish-green, and similarly, praseodymium results in various shades of yellow-green when incorporated into glasses. Many of praseodymium's industrial uses involve its ability to filter yellow light from light sources.
==Physical properties==
Praseodymium is the third member of the [[lanthanide]] series, and a member of the [[rare-earth metals]]. In the [[periodic table]], it appears between the lanthanides [[cerium]] to its left and [[neodymium]] to its right, and above the [[actinide]] [[protactinium]]. It is a [[ductile]] metal with a hardness comparable to that of [[silver]].<ref name="CRC">{{RubberBible86th}}</ref> Praseodymium is calculated to have a very large [[atomic radius]]; with a radius of 247 pm, [[barium]], [[rubidium]] and [[caesium]] are larger.<ref>{{cite journal |last1=Clementi |first1=E. |last2=Raimond |first2=D. L. |last3=Reinhardt |first3=W. P. |year=1967 |title=Atomic Screening Constants from SCF Functions. II. Atoms with 37 to 86 Electrons |journal=[[Journal of Chemical Physics]] |volume=47 |issue=4 |pages=1300–1307 |bibcode=1967JChPh..47.1300C |doi=10.1063/1.1712084}}</ref> However, observationally, it is usually 185 pm.<ref>{{cite journal |last=Slater|first=J. C. |year=1964 |title=Atomic Radii in Crystals |journal=[[Journal of Chemical Physics]] |volume=41 |issue=10 |pages=3199–3205 |bibcode=1964JChPh..41.3199S |doi=10.1063/1.1725697}}</ref>
Neutral praseodymium's 59 electrons are arranged in the [[electron configuration|configuration]] [Xe]4f<sup>3</sup>6s<sup>2</sup>.
Like most other lanthanides, praseodymium usually uses only three electrons as valence electrons, as the remaining 4f electrons are too strongly bound to engage in bonding: this is because the 4f orbitals penetrate the most through the inert xenon core of electrons to the nucleus, followed by 5d and 6s, and this penetration increases with higher ionic charge. Even so, praseodymium can in some compounds lose a fourth valence electron because it is early in the lanthanide series, where the nuclear charge is still low enough and the 4f subshell energy high enough to allow the removal of further valence electrons.<ref name="Greenwood1235">Greenwood and Earnshaw, pp. 1232–8</ref>
Similarly to the other early lanthanides, praseodymium has a [[close-packing of equal spheres|double hexagonal close-packed]] crystal structure at room temperature, called the alpha phase (α-Pr). At {{conv|795|C|K}} it transforms to a different [[Allotropy|allotrope]] that has a [[body-centered cubic]] structure (β-Pr), and it melts at {{conv|931|C|K}}.<ref name="Arblaster 2018" /><!-- Citation "Arblaster 2018" is given in the infobox: {{cite book |last=Arblaster |first= John W. |title=Selected Values of the Crystallographic Properties of Elements |publisher=ASM International |publication-place=Materials Park, Ohio |date=2018 |isbn=978-1-62708-155-9}}-->
Praseodymium, like all of the lanthanides, is [[paramagnetic]] at room temperature.<ref>{{cite book|last1=Cullity|first1=B. D.|last2=Graham|first2=C. D.|year=2011|title=Introduction to Magnetic Materials|publisher=[[John Wiley & Sons]]|isbn=978-1-118-21149-6}}</ref> Unlike some other rare-earth metals, which show [[antiferromagnetic]] or [[ferromagnetic]] ordering at low temperatures, praseodymium is paramagnetic at all temperatures above 1 K.<ref name="jackson" />
==Chemical properties==
[[File:Praseodymium(III) hydroxide.jpg|thumb|Praseodymium(III) hydroxide]]
Praseodymium metal tarnishes slowly in air, forming a [[spallation|spalling]] green oxide layer like [[iron]] rust; a centimetre-sized sample of praseodymium metal corrodes completely in about a year.<ref>{{cite web|url=http://www.elementsales.com/re_exp/index.htm |title = Rare-Earth Metal Long Term Air Exposure Test|access-date=2009-08-08}}</ref> It burns readily at 150 °C to form [[praseodymium(III,IV) oxide]], a [[nonstoichiometric compound]] approximating to Pr<sub>6</sub>O<sub>11</sub>:<ref name="webelements">{{cite web| url =https://www.webelements.com/praseodymium/chemistry.html| title =Chemical reactions of Praseodymium| publisher=Webelements| access-date=9 July 2016}}</ref>
:12 Pr + 11 O<sub>2</sub> → 2 Pr<sub>6</sub>O<sub>11</sub>
This may be reduced to [[praseodymium(III) oxide]] (Pr<sub>2</sub>O<sub>3</sub>) with hydrogen gas.<ref name="Greenwood1238">Greenwood and Earnshaw, pp. 1238–9</ref> [[Praseodymium(IV) oxide]], PrO<sub>2</sub>, is the most oxidised product of the combustion of praseodymium and can be obtained by either reaction of praseodymium metal with pure oxygen at 400 °C and 282 bar<ref name="Greenwood1238" /> or by disproportionation of Pr<sub>6</sub>O<sub>11</sub> in boiling acetic acid.<ref>{{cite journal|title= Hydrolytische spaltung von höheren oxiden des Praseodyms und des terbiums|author=Brauer, G. |author2=Pfeiffer, B. |date=1963|pages=171–176|volume=5|journal= Journal of the Less Common Metals|doi=10.1016/0022-5088(63)90010-9|issue=2}}</ref><ref>{{cite journal|title=Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2 |author1=Minasian, S.G. |author2=Batista, E.R. |author3=Booth, C.H. |author4=Clark, D.L. |author5=Keith, J.M. |author6=Kozimor, S.A. |author7=Lukens, W.W. |author8=Martin, R.L. |author9=Shuh, D.K. |author10=Stieber, C.E. |author11=Tylisczcak, T. |author12=Wen, Xiao-dong|date=2017|pages=18052–18064|volume=139|journal=Journal of the American Chemical Society|doi=10.1021/jacs.7b10361|pmid=29182343 |issue=49|osti=1485070 |s2cid=5382130 |url=https://escholarship.org/content/qt4dt0d19b/qt4dt0d19b.pdf?t=p0hj5c }}</ref> The reactivity of praseodymium conforms to [[periodic trends]], as it is one of the first and thus one of the largest lanthanides.<ref name="Greenwood1235" /> At 1000 °C, many praseodymium oxides with composition PrO<sub>2−''x''</sub> exist as disordered, nonstoichiometric phases with 0 < ''x'' < 0.25, but at 400–700 °C the oxide defects are instead ordered, creating phases of the general formula Pr<sub>''n''</sub>O<sub>2''n''−2</sub> with ''n'' = 4, 7, 9, 10, 11, 12, and ∞. These phases PrO<sub>''y''</sub> are sometimes labelled α and β′ (nonstoichiometric), β (''y'' = 1.833), δ (1.818), ε (1.8), ζ (1.778), ι (1.714), θ, and σ.<ref name="Greenwood643">Greenwood and Earnshaw, pp. 643–4</ref>
Praseodymium is an electropositive element and reacts slowly with cold water and quite quickly with hot water to form praseodymium(III) hydroxide:<ref name="webelements" />
:2 Pr (s) + 6 H<sub>2</sub>O (l) → 2 Pr(OH)<sub>3</sub> (aq) + 3 H<sub>2</sub> (g)
Praseodymium metal reacts with all the stable [[halogen]]s to form trihalides:<ref name="webelements" />
:2 Pr (s) + 3 F<sub>2</sub> (g) → 2 PrF<sub>3</sub> (s) [green]
:2 Pr (s) + 3 Cl<sub>2</sub> (g) → 2 PrCl<sub>3</sub> (s) [green]
:2 Pr (s) + 3 Br<sub>2</sub> (g) → 2 PrBr<sub>3</sub> (s) [green]
:2 Pr (s) + 3 I<sub>2</sub> (g) → 2 PrI<sub>3</sub> (s)
The [[Praseodymium(IV) fluoride|tetrafluoride, PrF<sub>4</sub>]], is also known, and is produced by reacting a mixture of [[sodium fluoride]] and [[praseodymium(III) fluoride]] with fluorine gas, producing Na<sub>2</sub>PrF<sub>6</sub>, following which sodium fluoride is removed from the reaction mixture with liquid [[hydrogen fluoride]].<ref name="Greenwood1240">Greenwood and Earnshaw, p. 1240–2</ref> Additionally, praseodymium forms a bronze [[praseodymium(II) iodide|diiodide]]; like the diiodides of lanthanum, cerium, and [[gadolinium]], it is a praseodymium(III) [[electride]] compound.<ref name="Greenwood1240" />
Praseodymium dissolves readily in dilute [[sulfuric acid]] to form solutions containing the [[chartreuse (color)|chartreuse]] Pr<sup>3+</sup> ions, which exist as [Pr(H<sub>2</sub>O)<sub>9</sub>]<sup>3+</sup> complexes:<ref name="webelements" /><ref name="Greenwood1242">Greenwood and Earnshaw, pp. 1242–4</ref>
:2 Pr (s) + 3 H<sub>2</sub>SO<sub>4</sub> (aq) → 2 Pr<sup>3+</sup> (aq) + 3 {{chem|SO|4|2-}} (aq) + 3 H<sub>2</sub> (g)
Dissolving praseodymium(IV) compounds in water does not result in solutions containing the yellow Pr<sup>4+</sup> ions;<ref name="SroorEdelmann2012">{{cite book|last1=Sroor|first1=Farid M.A.|title=Encyclopedia of Inorganic and Bioinorganic Chemistry|last2=Edelmann|first2=Frank T.|year=2012|doi=10.1002/9781119951438.eibc2033|chapter=Lanthanides: Tetravalent Inorganic|isbn=978-1-119-95143-8}}</ref> because of the high positive [[standard reduction potential]] of the Pr<sup>4+</sup>/Pr<sup>3+</sup> couple at +3.2 V, these ions are unstable in aqueous solution, oxidising water and being reduced to Pr<sup>3+</sup>. The value for the Pr<sup>3+</sup>/Pr couple is −2.35 V.<ref name="Greenwood1232">Greenwood and Earnshaw, pp. 1232–5</ref> However, in highly basic aqueous media, Pr<sup>4+</sup> ions can be generated by oxidation with [[ozone]].<ref>{{cite journal |title=Stabilization of Praseodymium(IV) and Terbium(IV) in Aqueous Carbonate Solution|author1=Hobart, D.E. |author2= Samhoun, K. |author3= Young, J.P. |author4=Norvell, V.E. |author5= Mamantov, G. |author6= Peterson, J. R. |date=1980 |pages=321–328 |volume=16 |journal=Inorganic and Nuclear Chemistry Letters |doi=10.1016/0020-1650(80)80069-9 |issue=5}}</ref>
Although praseodymium(V) in the bulk state is unknown, the existence of praseodymium in its +5 oxidation state (with the stable electron configuration of the preceding noble gas [[xenon]]) under noble-gas matrix isolation conditions was reported in 2016. The species assigned to the +5 state were identified as [PrO<sub>2</sub>]<sup>+</sup>, its O<sub>2</sub> and Ar adducts, and PrO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>).<ref>{{Cite journal|last1=Zhang|first1=Qingnan|last2=Hu|first2=Shu-Xian|last3=Qu|first3=Hui|last4=Su|first4=Jing|last5=Wang|first5=Guanjun|last6=Lu|first6=Jun-Bo|last7=Chen|first7=Mohua|last8=Zhou|first8=Mingfei|last9=Li|first9=Jun|date=2016-06-06|title=Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides|journal=Angewandte Chemie International Edition|language=en|volume=55|issue=24|pages=6896–6900|doi=10.1002/anie.201602196|pmid=27100273|issn=1521-3773}}</ref>
=== Organopraseodymium compounds ===
{{See also|Organolanthanide chemistry}}
Organopraseodymium compounds are very similar to [[organolanthanide chemistry|those of the other lanthanides]], as they all share an inability to undergo [[pi backbonding|π backbonding]]. They are thus mostly restricted to the mostly ionic [[cyclopentadienide]]s (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric.<ref name="Greenwood1248">Greenwood and Earnshaw, pp. 1248–9</ref> The coordination chemistry of praseodymium is largely that of the large, electropositive Pr<sup>3+</sup> ion, and is thus largely similar to those of the other early lanthanides La<sup>3+</sup>, Ce<sup>3+</sup>, and Nd<sup>3+</sup>. For instance, like lanthanum, cerium, and neodymium, praseodymium nitrates form both 4:3 and 1:1 complexes with [[18-crown-6]], whereas the middle lanthanides from [[promethium]] to [[gadolinium]] can only form the 4:3 complex and the later lanthanides from [[terbium]] to [[lutetium]] cannot successfully coordinate to all the ligands. Such praseodymium complexes have high but uncertain coordination numbers and poorly defined stereochemistry, with exceptions resulting from exceptionally bulky ligands such as the tricoordinate [Pr{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>]. There are also a few mixed oxides and fluorides involving praseodymium(IV), but it does not have an appreciable coordination chemistry in this oxidation state like its neighbour cerium.<ref name="Greenwood1244">Greenwood and Earnshaw, pp. 1244–8</ref> However, the first example of a molecular complex of praseodymium(IV) has recently been reported.<ref>{{cite journal |title= Accessing the +IV Oxidation State in Molecular Complexes of Praseodymium. |author1=Willauer, A.R. |author2=Palumbo, C.T. |author3=Fadaei-Tirani, F. |author4=Zivkovic, I. |author5=Douair, I. |author6=Maron, L. |author7=Mazzanti, M. |date=2020 |pages=489–493|volume=142 |journal=Journal of the American Chemical Society |issue=12 |doi=10.1021/jacs.0c01204|pmid=32134644 |s2cid=212564931 |url=http://infoscience.epfl.ch/record/277306 }}</ref>
==Isotopes==
{{main|Isotopes of praseodymium}}
Praseodymium has only one stable and naturally occurring isotope, <sup>141</sup>Pr. It is thus a [[mononuclidic element|mononuclidic]] and [[monoisotopic element]], and its [[standard atomic weight]] can be determined with high precision as it is a constant of nature. This isotope has 82 neutrons, which is a [[magic number (physics)|magic number]] that confers additional stability.<ref name="Audi">{{NUBASE 2003}}</ref> This isotope is produced in stars through the [[s-process|s-]] and [[r-process]]es (slow and rapid neutron capture, respectively).<ref name="Cameron">{{cite journal|last1=Cameron |first1=A. G. W. |year=1973 |title=Abundance of the Elements in the Solar System |url=http://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf |journal=Space Science Reviews |volume=15 |issue=1 |pages=121–146 |doi=10.1007/BF00172440 |bibcode=1973SSRv...15..121C |s2cid=120201972 |url-status=dead |archive-url=https://web.archive.org/web/20111021030549/http://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf |archive-date=2011-10-21 }}</ref> Thirty-eight other radioisotopes have been synthesized. All of these isotopes have half-lives under a day (and most under a minute), with the single exception of <sup>143</sup>Pr with a half-life of 13.6 days. Both <sup>143</sup>Pr and <sup>141</sup>Pr occur as [[fission product]]s of [[uranium]]. The primary decay mode of isotopes lighter than <sup>141</sup>Pr is [[positron emission]] or [[electron capture]] to [[isotopes of cerium]], while that of heavier isotopes is [[beta decay]] to [[isotopes of neodymium]].<ref name="Audi" />
==History==
[[File:Auer von Welsbach.jpg|upright|thumb|[[Carl Auer von Welsbach]] (1858–1929), discoverer of praseodymium in 1885.]]
In 1751, the Swedish mineralogist [[Axel Fredrik Cronstedt]] discovered a heavy mineral from the mine at [[Bastnäs]], later named [[cerite]]. Thirty years later, the fifteen-year-old [[Wilhelm Hisinger]], from the family owning the mine, sent a sample of it to [[Carl Scheele]], who did not find any new elements within. In 1803, after Hisinger had become an ironmaster, he returned to the mineral with [[Jöns Jacob Berzelius]] and isolated a new oxide, which they named ''ceria'' after the [[dwarf planet]] [[Ceres (dwarf planet)|Ceres]], which had been discovered two years earlier.<ref name="Emsley120">Emsley, pp. 120–5</ref> Ceria was simultaneously and independently isolated in Germany by [[Martin Heinrich Klaproth]].<ref name="Greenwood1424">Greenwood and Earnshaw, p. 1424</ref> Between 1839 and 1843, ceria was shown to be a mixture of oxides by the Swedish surgeon and chemist [[Carl Gustaf Mosander]], who lived in the same house as Berzelius; he separated out two other oxides, which he named ''lanthana'' and ''didymia''.<ref name= "XI">{{cite journal | doi = 10.1021/ed009p1231 | last = Weeks | first = Mary Elvira |author-link=Mary Elvira Weeks| title = The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium:Zirconium, Titanium, Cerium and Thorium | journal = The Journal of Chemical Education | date = 1932 | volume = 9 | issue = 7 | pages = 1231–1243 |bibcode = 1932JChEd...9.1231W }}</ref><ref name="Weeks">{{cite book |last1=Weeks |first1=Mary Elvira |title=The discovery of the elements |date= 1956 |publisher=Journal of Chemical Education |location=Easton, PA |url=https://archive.org/details/discoveryoftheel002045mbp |edition=6th }}</ref><ref name= "Virginia">{{cite journal |last1=Marshall |first1=James L. |last2=Marshall |first2=Virginia R. |title=Rediscovery of the elements: The Rare Earths – The Confusing Years |journal= The Hexagon |date=Winter 2015 |pages=72–77 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf |access-date=}}</ref> He partially decomposed a sample of [[cerium nitrate]] by roasting it in air and then treating the resulting oxide with dilute [[nitric acid]]. The metals that formed these oxides were thus named ''lanthanum'' and ''[[didymium]]''.<ref>(Berzelius) (1839) [https://archive.org/stream/ComptesRendusAcademieDesSciences0008/ComptesRendusAcadmieDesSciences-Tome008-Janvier-juin1839#page/n361/mode/1up "Nouveau métal"] (New metal), ''Comptes rendus'', ''8'' : 356–357. From p. 356: ''"L'oxide de cérium, extrait de la cérite par la procédé ordinaire, contient à peu près les deux cinquièmes de son poids de l'oxide du nouveau métal qui ne change que peu les propriétés du cérium, et qui s'y tient pour ainsi dire caché. Cette raison a engagé M. Mosander à donner au nouveau métal le nom de ''Lantane''."'' (The oxide of cerium, extracted from cerite by the usual procedure, contains almost two fifths of its weight in the oxide of the new metal, which differs only slightly from the properties of cerium, and which is held in it so to speak "hidden". This reason motivated Mr. Mosander to give to the new metal the name ''Lantane''.)</ref><ref>(Berzelius) (1839) [https://books.google.com/books?id=dF1KiX7MbSMC&pg=PA390 "Latanium — a new metal,"] ''Philosophical Magazine'', new series, '''14''' : 390–391.</ref>
While lanthanum turned out to be a pure element, didymium was not and turned out to be only a mixture of all the stable early lanthanides from praseodymium to [[europium]], as had been suspected by [[Marc Delafontaine]] after spectroscopic analysis, though he lacked the time to pursue its separation into its constituents. The heavy pair of [[samarium]] and europium were only removed in 1879 by [[Paul-Émile Lecoq de Boisbaudran]] and it was not until 1885 that [[Carl Auer von Welsbach]] separated didymium into praseodymium and neodymium.<ref name="Lost">{{cite book|ref=Fontani|last1=Fontani|first1=Marco|last2=Costa|first2=Mariagrazia|last3=Orna|first3=Virginia|title=The Lost Elements: The Periodic Table's Shadow Side|publisher=Oxford University Press|year=2014|url=https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA122|pages=122–123|isbn=978-0-19-938334-4}}</ref> Von Welsbach confirmed the separation by [[spectroscopic]] analysis, but the products were of relatively low purity. Since neodymium was a larger constituent of didymium than praseodymium, it kept the old name with disambiguation, while praseodymium was distinguished by the leek-green colour of its salts (Greek πρασιος, "leek green").<ref name="Greenwood1229">Greenwood and Earnshaw, p. 1229–32</ref> The composite nature of didymium had previously been suggested in 1882 by [[Bohuslav Brauner]], who did not experimentally pursue its separation.<ref name="Lost_p40">{{cite book|ref=Fontani|last1=Fontani|first1=Marco|last2=Costa|first2=Mariagrazia|last3=Orna|first3=Virginia|title=The Lost Elements: The Periodic Table's Shadow Side|url=https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA40|publisher=Oxford University Press|year=2014|page=40|isbn=978-0-19-938334-4}}</ref>
==Occurrence and production==
Praseodymium is not particularly rare, despite it being in the rare-earth metals, making up 9.2 mg/kg of the Earth's crust.<ref name=CRC97>Abundance of Elements in the Earth's Crust and in the Sea, ''CRC Handbook of Chemistry and Physics,'' 97th edition (2016–2017), p. 14-17</ref> Praseodymium's classification as a rare-earth metal comes from its rarity relative to "common earths" such as lime and magnesia, the few known minerals containing it for which extraction is commercially viable, as well as the length and complexity of extraction.<ref name="patnaik">{{cite book | last =Patnaik | first =Pradyot | date = 2003 | title =Handbook of Inorganic Chemical Compounds | publisher = McGraw-Hill | pages = 444–446| isbn =978-0-07-049439-8 | url= {{Google books |plainurl=yes |id=Xqj-TTzkvTEC |page=243 }} | access-date = 2009-06-06}}</ref> Although not particularly rare, praseodymium is never found as a dominant rare earth in praseodymium-bearing minerals. It is always preceded by cerium and lanthanum and usually also by neodymium.<ref>
{{cite web |url=https://www.mindat.org/ |title=Mindat.org |author=Hudson Institute of Mineralogy |date=1993–2018 |website=www.mindat.org |access-date=14 January 2018}}</ref>
[[File:Monazite acid cracking process.svg|frameless|center|730px]]
The Pr<sup>3+</sup> ion is similar in size to the early lanthanides of the cerium group (those from lanthanum up to [[samarium]] and [[europium]]) that immediately follow in the periodic table, and hence it tends to occur along with them in [[phosphate]], [[silicate]] and [[carbonate]] minerals, such as [[monazite]] (M<sup>III</sup>PO<sub>4</sub>) and [[bastnäsite]] (M<sup>III</sup>CO<sub>3</sub>F), where M refers to all the rare-earth metals except scandium and the radioactive [[promethium]] (mostly Ce, La, and Y, with somewhat less Nd and Pr).<ref name="Greenwood1229" /> Bastnäsite is usually lacking in [[thorium]] and the heavy lanthanides, and the purification of the light lanthanides from it is less involved. The ore, after being crushed and ground, is first treated with hot concentrated sulfuric acid, evolving carbon dioxide, [[hydrogen fluoride]], and [[silicon tetrafluoride]]. The product is then dried and leached with water, leaving the early lanthanide ions, including lanthanum, in solution.<ref name="Greenwood1229" />
The procedure for monazite, which usually contains all the rare earth, as well as thorium, is more involved. Monazite, because of its magnetic properties, can be separated by repeated electromagnetic separation. After separation, it is treated with hot concentrated sulfuric acid to produce water-soluble sulfates of rare earth. The acidic filtrates are partially neutralized with [[sodium hydroxide]] to pH 3–4, during which thorium precipitates as hydroxide and is removed. The solution is treated with [[ammonium oxalate]] to convert rare earth to their insoluble [[oxalate]]s, the oxalates are converted to oxides by annealing, and the oxides are dissolved in nitric acid. This last step excludes one of the main components, [[cerium]], whose oxide is insoluble in HNO<sub>3</sub>.<ref name="Patnaik">{{harvnb|Patnaik|2007|pp=[https://books.google.com/books?id=-CRRJBVv5d0C&pg=PA478 478–479]}}.</ref> Care must be taken when handling some of the residues as they contain [[radium-228|<sup>228</sup>Ra]], the daughter of <sup>232</sup>Th, which is a strong gamma emitter.<ref name="Greenwood1229" />
Praseodymium may then be separated from the other lanthanides via ion-exchange chromatography, or by using a solvent such as [[tributyl phosphate]] where the solubility of Ln<sup>3+</sup> increases as the atomic number increases. If ion-exchange chromatography is used, the mixture of lanthanides is loaded into one column of cation-exchange resin and Cu<sup>2+</sup> or Zn<sup>2+</sup> or Fe<sup>3+</sup> is loaded into the other. An aqueous solution of a complexing agent, known as the eluant (usually triammonium edtate), is passed through the columns, and Ln<sup>3+</sup> is displaced from the first column and redeposited in a compact band at the top of the column before being re-displaced by {{chem|NH|4|+}}. The [[Gibbs free energy]] of formation for Ln(edta·H) complexes increases along with the lanthanides by about one quarter from Ce<sup>3+</sup> to Lu<sup>3+</sup>, so that the Ln<sup>3+</sup> cations descend the development column in a band and are fractionated repeatedly, eluting from heaviest to lightest. They are then precipitated as their insoluble oxalates, burned to form the oxides, and then reduced to metals.<ref name="Greenwood1229" />
==Applications==
Leo Moser (not to be confused with [[Leo Moser|the mathematician of the same name]]), son of Ludwig Moser, founder of the [[Moser Glass]]works in what is now [[Karlovy Vary]] in the Czech Republic, investigated the use of praseodymium in glass coloration in the late 1920s, yielding a yellow-green glass given the name "Prasemit". However, at that time far cheaper colorants could give a similar color, so Prasemit was not popular, few pieces were made, and examples are now extremely rare. Moser also blended praseodymium with neodymium to produce "Heliolite" glass ("Heliolit" in [[German language|German]]),<!--http://books.google.de/books?id=36dRAAAAMAAJ&q=praseodymium+glass+moser&dq=praseodymium+glass+moser&hl=de&ei=Ptt0TLLYE5KHswalhr2IBg&sa=X&oi=book_result&ct=result&resnum=2&ved=0CD4Q6AEwAQ--> which was more widely accepted. The first enduring commercial use of purified praseodymium, which continues today, is in the form of a yellow-orange "Praseodymium Yellow" stain for ceramics, which is a solid solution in the [[zirconium(IV) silicate|zircon]] lattice. This stain has no hint of green in it; by contrast, at sufficiently high loadings, praseodymium glass is distinctly green rather than pure yellow.<ref>{{cite journal | last1 = Kreidl | first1 = Norbert J. | title = RARE EARTHS* | journal = Journal of the American Ceramic Society | volume = 25 | pages = 141–143 | date = 1942 | doi = 10.1111/j.1151-2916.1942.tb14363.x | issue = 5}}</ref>
Like many other lanthanides, praseodymium's shielded [[f-orbital]]s allow for long [[excited state]] lifetimes and high [[luminescence]] yields. Pr<sup>3+</sup> as a [[Doping (semiconductor)|dopant]] ion therefore sees many applications in [[optics]] and [[photonics]]. These include [[Pr:YLF laser|DPSS-lasers]], single-mode fiber [[optical amplifier]]s,<ref>{{cite journal|last1=Jha|first1=A.|last2=Naftaly|first2=M.|last3=Jordery|first3=S.|last4=Samson|first4=B. N.|last5=Taylor|first5=E. R.|last6=Hewak|first6=D.|last7=Payne|first7=D. N.|last8=Poulain|first8=M.|last9=Zhang|first9=G.|display-authors=4|date=1995|title=Design and fabrication of Pr3+-doped fluoride glass optical fibres for efficient 1.3 mu m amplifiers|url=https://eprints.soton.ac.uk/78174/1/918.pdf|journal=Pure and Applied Optics: Journal of the European Optical Society Part A|volume=4|issue=4|pages=417|bibcode=1995PApOp...4..417J|doi=10.1088/0963-9659/4/4/019}}</ref> fiber lasers,<ref>{{Cite journal|last1=Smart|first1=R.G.|last2=Hanna|first2=D.C.|last3=Tropper|first3=A.C.|last4=Davey|first4=S.T.|last5=Carter|first5=S.F.|last6=Szebesta|first6=D.|date=1991|title=Cw room temperature upconversion lasing at blue, green and red wavelengths in infrared-pumped Pr3+-doped fluoride fibre|url=https://digital-library.theiet.org/content/journals/10.1049/el_19910817|journal=Electronics Letters|language=en|volume=27|issue=14|pages=1307|doi=10.1049/el:19910817|bibcode=1991ElL....27.1307S}}</ref> [[upconverting nanoparticles]]<ref>{{Cite journal|last1=de Prinse|first1=Thomas J.|last2=Karami|first2=Afshin|last3=Moffatt|first3=Jillian E.|last4=Payten|first4=Thomas B.|last5=Tsiminis|first5=Georgios|last6=Teixeira|first6=Lewis Da Silva|last7=Bi|first7=Jingxiu|last8=Kee|first8=Tak W.|last9=Klantsataya|first9=Elizaveta|last10=Sumby|first10=Christopher J.|last11=Spooner|first11=Nigel A.|date=2021|title=Dual Laser Study of Non‐Degenerate Two Wavelength Upconversion Demonstrated in Sensitizer‐Free NaYF 4 :Pr Nanoparticles|url=https://onlinelibrary.wiley.com/doi/10.1002/adom.202001903|journal=Advanced Optical Materials|volume=9|issue=7|language=en|pages=2001903|doi=10.1002/adom.202001903|s2cid=234059121|issn=2195-1071|hdl=2440/139814|hdl-access=free}}</ref><ref>{{Cite journal|last1=Kolesov|first1=Roman|last2=Reuter|first2=Rolf|last3=Xia|first3=Kangwei|last4=Stöhr|first4=Rainer|last5=Zappe|first5=Andrea|last6=Wrachtrup|first6=Jörg|date=2011-10-31|title=Super-resolution upconversion microscopy of praseodymium-doped yttrium aluminum garnet nanoparticles|url=https://link.aps.org/doi/10.1103/PhysRevB.84.153413|journal=Physical Review B|language=en|volume=84|issue=15|pages=153413|doi=10.1103/PhysRevB.84.153413|bibcode=2011PhRvB..84o3413K|issn=1098-0121}}</ref> as well as activators in red, green, blue, and ultraviolet phosphors.<ref name="Ullmann" /> Silicate crystals doped with praseodymium ions have also been used to [[slow light|slow a light pulse]] down to a few hundred meters per second.<ref name="ANUPressStopLight">{{cite web|title=ANU team stops light in quantum leap|url=http://info.anu.edu.au/ovc/Media/Media_Releases/2005/August/290805_stop_light|access-date=18 May 2009}}</ref>
As the lanthanides are so similar, praseodymium can substitute for most other lanthanides without significant loss of function, and indeed many applications such as [[mischmetal]] and [[ferrocerium]] alloys involve variable mixes of several lanthanides, including small quantities of praseodymium. The following more modern applications involve praseodymium specifically or at least praseodymium in a small subset of the lanthanides:<ref name="Ullmann" />
* In combination with neodymium, another rare-earth element, praseodymium is used to create high-power magnets notable for their strength and durability.<ref name="IAMGOLD">[http://www.iamgold.com/files/REE101_April_2012.pdf Rare Earth Elements 101] {{webarchive|url=https://web.archive.org/web/20131122140504/http://www.iamgold.com/files/REE101_April_2012.pdf |date=2013-11-22 }}, IAMGOLD Corporation, April 2012, pp. 5, 7.</ref> In general, most alloys of the cerium-group rare earths ([[lanthanum]] through [[samarium]]) with 3d [[transition metal]]s give extremely stable magnets that are often used in small equipment, such as motors, printers, watches, headphones, loudspeakers, and magnetic storage.<ref name="Ullmann">{{Ullmann|volume=31|page=183–227|last1=McGill|first1=Ian|contribution=Rare Earth Elements|doi=10.1002/14356007.a22_607}}</ref>
*Praseodymium–[[nickel]] intermetallic (PrNi<sub>5</sub>) has such a strong [[Magnetic refrigeration#The magnetocaloric effect|magnetocaloric effect]] that it has allowed scientists to approach within one thousandth of a degree of [[absolute zero]].<ref name="Emsley423" />
* As an [[alloy]]ing agent with [[magnesium]] to create high-strength metals that are used in [[aircraft engine]]s; [[yttrium]] and [[neodymium]] are also viable substitutes.<ref>{{cite book| first = L. L. |last = Rokhlin | title = Magnesium alloys containing rare earth metals: structure and properties| publisher = CRC Press| date = 2003| isbn =978-0-415-28414-1}}</ref><ref>{{cite journal | last1 = Suseelan Nair | first1 = K. | last2 = Mittal | first2 = M. C. | title = Rare Earths in Magnesium Alloys | journal = Materials Science Forum | volume = 30 | pages = 89–104 | date = 1988 | doi = 10.4028/www.scientific.net/MSF.30.89| s2cid = 136992837 }}</ref>
* Praseodymium is present in the rare-earth mixture whose fluoride forms the core of [[carbon arc light]]s, which are used in the [[movie studio|motion picture industry]] for [[studio]] lighting and [[Image projector|projector]] lights.<ref name="Emsley423">Emsley, pp. 423–5</ref>
* Praseodymium [[chemical compound|compounds]] give [[glass]]es, [[vitreous enamel|enamels]] and ceramics a [[yellow]] color.<ref name="CRC" /><ref name="Ullmann" />
* Praseodymium is a component of [[didymium]] glass, which is used to make certain types of [[welding|welder]]'s and [[glass blowing|glass blower]]'s [[goggles]].<ref name="CRC" />
* Praseodymium oxide in solid solution with [[ceria]] or [[ceria-zirconia]] has been used as an [[oxidation]] [[catalyst]].<ref>{{cite journal| doi = 10.1021/jp0768524| title = Nanostructured Praseodymium Oxide: Preparation, Structure, and Catalytic Properties| date = 2008| display-authors = 4| author = Borchert, Y.| author2 = Sonstrom, P.| author3 = Wilhelm, M.| author4 = Borchert, H.| author5 = Baumer, M.| journal = Journal of Physical Chemistry C| volume = 112| pages = 3054| issue = 8}}</ref>
Due to its role in permanent magnets used for wind turbines, it has been argued that praseodymium will be one of the main objects of geopolitical competition in a world running on renewable energy. However, this perspective has been criticized for failing to recognize that most wind turbines do not use permanent magnets and for underestimating the power of economic incentives for expanded production.<ref>{{Cite journal|last=Overland|first=Indra|date=2019-03-01|title=The geopolitics of renewable energy: Debunking four emerging myths|journal=Energy Research & Social Science|volume=49|pages=36–40|doi=10.1016/j.erss.2018.10.018|issn=2214-6296|doi-access=free}}</ref><ref name="Klinger">{{cite book |last1=Klinger |first1=Julie Michelle |title=Rare earth frontiers : from terrestrial subsoils to lunar landscapes |date=2017 |publisher=Cornell University Press |location=Ithaca, NY |isbn=978-1501714603 |jstor=10.7591/j.ctt1w0dd6d }}</ref>
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==Biological role and precautions==
The early lanthanides have been found to be essential to some [[methanotrophic]] bacteria living in [[Mudpot|volcanic mudpots]], such as ''[[Methylacidiphilum fumariolicum]]'': lanthanum, cerium, praseodymium, and neodymium are about equally effective.<ref>{{cite journal |doi=10.1111/1462-2920.12249 |pmid=24034209 |title=Rare earth metals are essential for methanotrophic life in volcanic mudpots |date=2013 |last1=Pol |first1=Arjan |last2=Barends |first2=Thomas R. M. |last3=Dietl |first3=Andreas |last4=Khadem |first4=Ahmad F. |last5=Eygensteyn |first5=Jelle |last6=Jetten |first6=Mike S. M. |last7=Op Den Camp |first7=Huub J. M. |journal=Environmental Microbiology |volume=16 |issue=1 |pages=255–64}}</ref><ref>{{cite journal | last1=Kang | first1=L. | last2=Shen | first2=Z. | last3=Jin | first3=C. | title=Neodymium cations Nd<sup>3+</sup> were transported to the interior of ''Euglena gracilis'' | issue=277 | journal=Chin. Sci. Bull. | volume=45 | pages=585–592 | date=2000 | doi=10.1007/BF02886032| bibcode=2000ChSBu..45..585K | s2cid=95983365 }}</ref> Praseodymium is otherwise not known to have a biological role in any other organisms, but it is not very toxic either. Intravenous injection of rare earths into animals has been known to impair liver function, but the main side effects from inhalation of rare-earth oxides in humans come from radioactive [[thorium]] and [[uranium]] impurities.<ref name="Ullmann" />
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==Notes==
{{Notelist}}
==References==
{{Reflist|30em}}
==Bibliography==
*{{cite book|author=Emsley, John|title=Nature's Building Blocks: An A-Z Guide to the Elements|date=2011|publisher=[[Oxford University Press]]|isbn=978-0-19-960563-7}}
*{{Greenwood&Earnshaw2nd}}
== Further reading ==
* R. J. Callow, ''The Industrial Chemistry of the Lanthanons, Yttrium, Thorium, and Uranium'', Pergamon Press, 1967.
* Bouhani, H (2020). "Engineering the magnetocaloric properties of PrVO3 epitaxial oxide thin films by strain effects". Applied Physics Letters. 117 (7). arXiv:2008.09193. doi:10.1063/5.0021031.
== External links ==
{{Commons|Praseodymium}}
{{Wiktionary|praseodymium}}
* [http://www.webelements.com/webelements/elements/text/Pr/index.html WebElements.com—Praseodymium]
* [http://education.jlab.org/itselemental/ele059.html It's Elemental—The Element Praseodymium]
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{{Periodic table (navbox)}}
{{Praseodymium compounds}}
{{Authority control}}
[[Category:Praseodymium| ]]
[[Category:Chemical elements]]
[[Category:Chemical elements with double hexagonal close-packed structure]]
[[Category:Lanthanides]]
[[Category:Reducing agents]]' |
New page wikitext, after the edit (new_wikitext) | '{{good article}}
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{{Infobox praseodymium}}
'''Praseodymium''' is a [[chemical element]]; it has [[Symbol (chemistry)|symbol]] '''Pr''' and the [[atomic number]] 59. It is the third member of the [[lanthanide]] series and is considered one of the [[rare-earth metal]]s. It is a soft, silvery, malleable and ductile [[metal]], valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in [[Native element mineral|native form]], and pure praseodymium metal slowly develops a green oxide coating when exposed to air.
Praseodymium always occurs naturally together with the other rare-earth metals. It is the sixth-most abundant rare-earth element and fourth-most abundant lanthanide, making up 9.1 [[parts per million]] of the Earth's crust, an abundance similar to that of [[boron]]. In 1841, Swedish chemist [[Carl Gustav Mosander]] extracted a rare-earth oxide residue he called [[didymium]] from a residue he called "lanthana", in turn separated from [[cerium]] salts. In 1885, the Austrian chemist [[Carl Auer von Welsbach]] separated didymium into two elements that gave salts of different colours, which he named praseodymium and [[neodymium]]. The name fart balls jucise comes from the Ancient Greek {{lang|grc|πράσινος}} ({{transl|grc|prasinos}}), meaning '[[leek]]-green', and {{lang|grc|δίδυμος}} ({{transl|grc|didymos}}) 'twin'.
Like most [[rare-earth element]]s, praseodymium most readily forms the +3 [[oxidation state]], which is the only stable state in [[aqueous solution]], although the +4 oxidation state is known in some solid compounds and, uniquely among the lanthanides, the +5 oxidation state is attainable in [[Matrix isolation|matrix-isolation conditions]]. The 0, +1, and +2 oxidation states are rarely found. Aqueous praseodymium ions are yellowish-green, and similarly, praseodymium results in various shades of yellow-green when incorporated into glasses. Many of praseodymium's industrial uses involve its ability to filter yellow light from light sources.
==Physical properties==
Praseodymium is the third member of the [[lanthanide]] series, and a member of the [[rare-earth metals]]. In the [[periodic table]], it appears between the lanthanides [[cerium]] to its left and [[neodymium]] to its right, and above the [[actinide]] [[protactinium]]. It is a [[ductile]] metal with a hardness comparable to that of [[silver]].<ref name="CRC">{{RubberBible86th}}</ref> Praseodymium is calculated to have a very large [[atomic radius]]; with a radius of 247 pm, [[barium]], [[rubidium]] and [[caesium]] are larger.<ref>{{cite journal |last1=Clementi |first1=E. |last2=Raimond |first2=D. L. |last3=Reinhardt |first3=W. P. |year=1967 |title=Atomic Screening Constants from SCF Functions. II. Atoms with 37 to 86 Electrons |journal=[[Journal of Chemical Physics]] |volume=47 |issue=4 |pages=1300–1307 |bibcode=1967JChPh..47.1300C |doi=10.1063/1.1712084}}</ref> However, observationally, it is usually 185 pm.<ref>{{cite journal |last=Slater|first=J. C. |year=1964 |title=Atomic Radii in Crystals |journal=[[Journal of Chemical Physics]] |volume=41 |issue=10 |pages=3199–3205 |bibcode=1964JChPh..41.3199S |doi=10.1063/1.1725697}}</ref>
Neutral praseodymium's 59 electrons are arranged in the [[electron configuration|configuration]] [Xe]4f<sup>3</sup>6s<sup>2</sup>.
Like most other lanthanides, praseodymium usually uses only three electrons as valence electrons, as the remaining 4f electrons are too strongly bound to engage in bonding: this is because the 4f orbitals penetrate the most through the inert xenon core of electrons to the nucleus, followed by 5d and 6s, and this penetration increases with higher ionic charge. Even so, praseodymium can in some compounds lose a fourth valence electron because it is early in the lanthanide series, where the nuclear charge is still low enough and the 4f subshell energy high enough to allow the removal of further valence electrons.<ref name="Greenwood1235">Greenwood and Earnshaw, pp. 1232–8</ref>
Similarly to the other early lanthanides, praseodymium has a [[close-packing of equal spheres|double hexagonal close-packed]] crystal structure at room temperature, called the alpha phase (α-Pr). At {{conv|795|C|K}} it transforms to a different [[Allotropy|allotrope]] that has a [[body-centered cubic]] structure (β-Pr), and it melts at {{conv|931|C|K}}.<ref name="Arblaster 2018" /><!-- Citation "Arblaster 2018" is given in the infobox: {{cite book |last=Arblaster |first= John W. |title=Selected Values of the Crystallographic Properties of Elements |publisher=ASM International |publication-place=Materials Park, Ohio |date=2018 |isbn=978-1-62708-155-9}}-->
Praseodymium, like all of the lanthanides, is [[paramagnetic]] at room temperature.<ref>{{cite book|last1=Cullity|first1=B. D.|last2=Graham|first2=C. D.|year=2011|title=Introduction to Magnetic Materials|publisher=[[John Wiley & Sons]]|isbn=978-1-118-21149-6}}</ref> Unlike some other rare-earth metals, which show [[antiferromagnetic]] or [[ferromagnetic]] ordering at low temperatures, praseodymium is paramagnetic at all temperatures above 1 K.<ref name="jackson" />
==Chemical properties==
[[File:Praseodymium(III) hydroxide.jpg|thumb|Praseodymium(III) hydroxide]]
Praseodymium metal tarnishes slowly in air, forming a [[spallation|spalling]] green oxide layer like [[iron]] rust; a centimetre-sized sample of praseodymium metal corrodes completely in about a year.<ref>{{cite web|url=http://www.elementsales.com/re_exp/index.htm |title = Rare-Earth Metal Long Term Air Exposure Test|access-date=2009-08-08}}</ref> It burns readily at 150 °C to form [[praseodymium(III,IV) oxide]], a [[nonstoichiometric compound]] approximating to Pr<sub>6</sub>O<sub>11</sub>:<ref name="webelements">{{cite web| url =https://www.webelements.com/praseodymium/chemistry.html| title =Chemical reactions of Praseodymium| publisher=Webelements| access-date=9 July 2016}}</ref>
:12 Pr + 11 O<sub>2</sub> → 2 Pr<sub>6</sub>O<sub>11</sub>
This may be reduced to [[praseodymium(III) oxide]] (Pr<sub>2</sub>O<sub>3</sub>) with hydrogen gas.<ref name="Greenwood1238">Greenwood and Earnshaw, pp. 1238–9</ref> [[Praseodymium(IV) oxide]], PrO<sub>2</sub>, is the most oxidised product of the combustion of praseodymium and can be obtained by either reaction of praseodymium metal with pure oxygen at 400 °C and 282 bar<ref name="Greenwood1238" /> or by disproportionation of Pr<sub>6</sub>O<sub>11</sub> in boiling acetic acid.<ref>{{cite journal|title= Hydrolytische spaltung von höheren oxiden des Praseodyms und des terbiums|author=Brauer, G. |author2=Pfeiffer, B. |date=1963|pages=171–176|volume=5|journal= Journal of the Less Common Metals|doi=10.1016/0022-5088(63)90010-9|issue=2}}</ref><ref>{{cite journal|title=Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2 |author1=Minasian, S.G. |author2=Batista, E.R. |author3=Booth, C.H. |author4=Clark, D.L. |author5=Keith, J.M. |author6=Kozimor, S.A. |author7=Lukens, W.W. |author8=Martin, R.L. |author9=Shuh, D.K. |author10=Stieber, C.E. |author11=Tylisczcak, T. |author12=Wen, Xiao-dong|date=2017|pages=18052–18064|volume=139|journal=Journal of the American Chemical Society|doi=10.1021/jacs.7b10361|pmid=29182343 |issue=49|osti=1485070 |s2cid=5382130 |url=https://escholarship.org/content/qt4dt0d19b/qt4dt0d19b.pdf?t=p0hj5c }}</ref> The reactivity of praseodymium conforms to [[periodic trends]], as it is one of the first and thus one of the largest lanthanides.<ref name="Greenwood1235" /> At 1000 °C, many praseodymium oxides with composition PrO<sub>2−''x''</sub> exist as disordered, nonstoichiometric phases with 0 < ''x'' < 0.25, but at 400–700 °C the oxide defects are instead ordered, creating phases of the general formula Pr<sub>''n''</sub>O<sub>2''n''−2</sub> with ''n'' = 4, 7, 9, 10, 11, 12, and ∞. These phases PrO<sub>''y''</sub> are sometimes labelled α and β′ (nonstoichiometric), β (''y'' = 1.833), δ (1.818), ε (1.8), ζ (1.778), ι (1.714), θ, and σ.<ref name="Greenwood643">Greenwood and Earnshaw, pp. 643–4</ref>
Praseodymium is an electropositive element and reacts slowly with cold water and quite quickly with hot water to form praseodymium(III) hydroxide:<ref name="webelements" />
:2 Pr (s) + 6 H<sub>2</sub>O (l) → 2 Pr(OH)<sub>3</sub> (aq) + 3 H<sub>2</sub> (g)
Praseodymium metal reacts with all the stable [[halogen]]s to form trihalides:<ref name="webelements" />
:2 Pr (s) + 3 F<sub>2</sub> (g) → 2 PrF<sub>3</sub> (s) [green]
:2 Pr (s) + 3 Cl<sub>2</sub> (g) → 2 PrCl<sub>3</sub> (s) [green]
:2 Pr (s) + 3 Br<sub>2</sub> (g) → 2 PrBr<sub>3</sub> (s) [green]
:2 Pr (s) + 3 I<sub>2</sub> (g) → 2 PrI<sub>3</sub> (s)
The [[Praseodymium(IV) fluoride|tetrafluoride, PrF<sub>4</sub>]], is also known, and is produced by reacting a mixture of [[sodium fluoride]] and [[praseodymium(III) fluoride]] with fluorine gas, producing Na<sub>2</sub>PrF<sub>6</sub>, following which sodium fluoride is removed from the reaction mixture with liquid [[hydrogen fluoride]].<ref name="Greenwood1240">Greenwood and Earnshaw, p. 1240–2</ref> Additionally, praseodymium forms a bronze [[praseodymium(II) iodide|diiodide]]; like the diiodides of lanthanum, cerium, and [[gadolinium]], it is a praseodymium(III) [[electride]] compound.<ref name="Greenwood1240" />
Praseodymium dissolves readily in dilute [[sulfuric acid]] to form solutions containing the [[chartreuse (color)|chartreuse]] Pr<sup>3+</sup> ions, which exist as [Pr(H<sub>2</sub>O)<sub>9</sub>]<sup>3+</sup> complexes:<ref name="webelements" /><ref name="Greenwood1242">Greenwood and Earnshaw, pp. 1242–4</ref>
:2 Pr (s) + 3 H<sub>2</sub>SO<sub>4</sub> (aq) → 2 Pr<sup>3+</sup> (aq) + 3 {{chem|SO|4|2-}} (aq) + 3 H<sub>2</sub> (g)
Dissolving praseodymium(IV) compounds in water does not result in solutions containing the yellow Pr<sup>4+</sup> ions;<ref name="SroorEdelmann2012">{{cite book|last1=Sroor|first1=Farid M.A.|title=Encyclopedia of Inorganic and Bioinorganic Chemistry|last2=Edelmann|first2=Frank T.|year=2012|doi=10.1002/9781119951438.eibc2033|chapter=Lanthanides: Tetravalent Inorganic|isbn=978-1-119-95143-8}}</ref> because of the high positive [[standard reduction potential]] of the Pr<sup>4+</sup>/Pr<sup>3+</sup> couple at +3.2 V, these ions are unstable in aqueous solution, oxidising water and being reduced to Pr<sup>3+</sup>. The value for the Pr<sup>3+</sup>/Pr couple is −2.35 V.<ref name="Greenwood1232">Greenwood and Earnshaw, pp. 1232–5</ref> However, in highly basic aqueous media, Pr<sup>4+</sup> ions can be generated by oxidation with [[ozone]].<ref>{{cite journal |title=Stabilization of Praseodymium(IV) and Terbium(IV) in Aqueous Carbonate Solution|author1=Hobart, D.E. |author2= Samhoun, K. |author3= Young, J.P. |author4=Norvell, V.E. |author5= Mamantov, G. |author6= Peterson, J. R. |date=1980 |pages=321–328 |volume=16 |journal=Inorganic and Nuclear Chemistry Letters |doi=10.1016/0020-1650(80)80069-9 |issue=5}}</ref>
Although praseodymium(V) in the bulk state is unknown, the existence of praseodymium in its +5 oxidation state (with the stable electron configuration of the preceding noble gas [[xenon]]) under noble-gas matrix isolation conditions was reported in 2016. The species assigned to the +5 state were identified as [PrO<sub>2</sub>]<sup>+</sup>, its O<sub>2</sub> and Ar adducts, and PrO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>).<ref>{{Cite journal|last1=Zhang|first1=Qingnan|last2=Hu|first2=Shu-Xian|last3=Qu|first3=Hui|last4=Su|first4=Jing|last5=Wang|first5=Guanjun|last6=Lu|first6=Jun-Bo|last7=Chen|first7=Mohua|last8=Zhou|first8=Mingfei|last9=Li|first9=Jun|date=2016-06-06|title=Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides|journal=Angewandte Chemie International Edition|language=en|volume=55|issue=24|pages=6896–6900|doi=10.1002/anie.201602196|pmid=27100273|issn=1521-3773}}</ref>
=== Organopraseodymium compounds ===
{{See also|Organolanthanide chemistry}}
Organopraseodymium compounds are very similar to [[organolanthanide chemistry|those of the other lanthanides]], as they all share an inability to undergo [[pi backbonding|π backbonding]]. They are thus mostly restricted to the mostly ionic [[cyclopentadienide]]s (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric.<ref name="Greenwood1248">Greenwood and Earnshaw, pp. 1248–9</ref> The coordination chemistry of praseodymium is largely that of the large, electropositive Pr<sup>3+</sup> ion, and is thus largely similar to those of the other early lanthanides La<sup>3+</sup>, Ce<sup>3+</sup>, and Nd<sup>3+</sup>. For instance, like lanthanum, cerium, and neodymium, praseodymium nitrates form both 4:3 and 1:1 complexes with [[18-crown-6]], whereas the middle lanthanides from [[promethium]] to [[gadolinium]] can only form the 4:3 complex and the later lanthanides from [[terbium]] to [[lutetium]] cannot successfully coordinate to all the ligands. Such praseodymium complexes have high but uncertain coordination numbers and poorly defined stereochemistry, with exceptions resulting from exceptionally bulky ligands such as the tricoordinate [Pr{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>]. There are also a few mixed oxides and fluorides involving praseodymium(IV), but it does not have an appreciable coordination chemistry in this oxidation state like its neighbour cerium.<ref name="Greenwood1244">Greenwood and Earnshaw, pp. 1244–8</ref> However, the first example of a molecular complex of praseodymium(IV) has recently been reported.<ref>{{cite journal |title= Accessing the +IV Oxidation State in Molecular Complexes of Praseodymium. |author1=Willauer, A.R. |author2=Palumbo, C.T. |author3=Fadaei-Tirani, F. |author4=Zivkovic, I. |author5=Douair, I. |author6=Maron, L. |author7=Mazzanti, M. |date=2020 |pages=489–493|volume=142 |journal=Journal of the American Chemical Society |issue=12 |doi=10.1021/jacs.0c01204|pmid=32134644 |s2cid=212564931 |url=http://infoscience.epfl.ch/record/277306 }}</ref>
==Isotopes==
{{main|Isotopes of praseodymium}}
Praseodymium has only one stable and naturally occurring isotope, <sup>141</sup>Pr. It is thus a [[mononuclidic element|mononuclidic]] and [[monoisotopic element]], and its [[standard atomic weight]] can be determined with high precision as it is a constant of nature. This isotope has 82 neutrons, which is a [[magic number (physics)|magic number]] that confers additional stability.<ref name="Audi">{{NUBASE 2003}}</ref> This isotope is produced in stars through the [[s-process|s-]] and [[r-process]]es (slow and rapid neutron capture, respectively).<ref name="Cameron">{{cite journal|last1=Cameron |first1=A. G. W. |year=1973 |title=Abundance of the Elements in the Solar System |url=http://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf |journal=Space Science Reviews |volume=15 |issue=1 |pages=121–146 |doi=10.1007/BF00172440 |bibcode=1973SSRv...15..121C |s2cid=120201972 |url-status=dead |archive-url=https://web.archive.org/web/20111021030549/http://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf |archive-date=2011-10-21 }}</ref> Thirty-eight other radioisotopes have been synthesized. All of these isotopes have half-lives under a day (and most under a minute), with the single exception of <sup>143</sup>Pr with a half-life of 13.6 days. Both <sup>143</sup>Pr and <sup>141</sup>Pr occur as [[fission product]]s of [[uranium]]. The primary decay mode of isotopes lighter than <sup>141</sup>Pr is [[positron emission]] or [[electron capture]] to [[isotopes of cerium]], while that of heavier isotopes is [[beta decay]] to [[isotopes of neodymium]].<ref name="Audi" />
==History==
[[File:Auer von Welsbach.jpg|upright|thumb|[[Carl Auer von Welsbach]] (1858–1929), discoverer of praseodymium in 1885.]]
In 1751, the Swedish mineralogist [[Axel Fredrik Cronstedt]] discovered a heavy mineral from the mine at [[Bastnäs]], later named [[cerite]]. Thirty years later, the fifteen-year-old [[Wilhelm Hisinger]], from the family owning the mine, sent a sample of it to [[Carl Scheele]], who did not find any new elements within. In 1803, after Hisinger had become an ironmaster, he returned to the mineral with [[Jöns Jacob Berzelius]] and isolated a new oxide, which they named ''ceria'' after the [[dwarf planet]] [[Ceres (dwarf planet)|Ceres]], which had been discovered two years earlier.<ref name="Emsley120">Emsley, pp. 120–5</ref> Ceria was simultaneously and independently isolated in Germany by [[Martin Heinrich Klaproth]].<ref name="Greenwood1424">Greenwood and Earnshaw, p. 1424</ref> Between 1839 and 1843, ceria was shown to be a mixture of oxides by the Swedish surgeon and chemist [[Carl Gustaf Mosander]], who lived in the same house as Berzelius; he separated out two other oxides, which he named ''lanthana'' and ''didymia''.<ref name= "XI">{{cite journal | doi = 10.1021/ed009p1231 | last = Weeks | first = Mary Elvira |author-link=Mary Elvira Weeks| title = The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium:Zirconium, Titanium, Cerium and Thorium | journal = The Journal of Chemical Education | date = 1932 | volume = 9 | issue = 7 | pages = 1231–1243 |bibcode = 1932JChEd...9.1231W }}</ref><ref name="Weeks">{{cite book |last1=Weeks |first1=Mary Elvira |title=The discovery of the elements |date= 1956 |publisher=Journal of Chemical Education |location=Easton, PA |url=https://archive.org/details/discoveryoftheel002045mbp |edition=6th }}</ref><ref name= "Virginia">{{cite journal |last1=Marshall |first1=James L. |last2=Marshall |first2=Virginia R. |title=Rediscovery of the elements: The Rare Earths – The Confusing Years |journal= The Hexagon |date=Winter 2015 |pages=72–77 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf |access-date=}}</ref> He partially decomposed a sample of [[cerium nitrate]] by roasting it in air and then treating the resulting oxide with dilute [[nitric acid]]. The metals that formed these oxides were thus named ''lanthanum'' and ''[[didymium]]''.<ref>(Berzelius) (1839) [https://archive.org/stream/ComptesRendusAcademieDesSciences0008/ComptesRendusAcadmieDesSciences-Tome008-Janvier-juin1839#page/n361/mode/1up "Nouveau métal"] (New metal), ''Comptes rendus'', ''8'' : 356–357. From p. 356: ''"L'oxide de cérium, extrait de la cérite par la procédé ordinaire, contient à peu près les deux cinquièmes de son poids de l'oxide du nouveau métal qui ne change que peu les propriétés du cérium, et qui s'y tient pour ainsi dire caché. Cette raison a engagé M. Mosander à donner au nouveau métal le nom de ''Lantane''."'' (The oxide of cerium, extracted from cerite by the usual procedure, contains almost two fifths of its weight in the oxide of the new metal, which differs only slightly from the properties of cerium, and which is held in it so to speak "hidden". This reason motivated Mr. Mosander to give to the new metal the name ''Lantane''.)</ref><ref>(Berzelius) (1839) [https://books.google.com/books?id=dF1KiX7MbSMC&pg=PA390 "Latanium — a new metal,"] ''Philosophical Magazine'', new series, '''14''' : 390–391.</ref>
While lanthanum turned out to be a pure element, didymium was not and turned out to be only a mixture of all the stable early lanthanides from praseodymium to [[europium]], as had been suspected by [[Marc Delafontaine]] after spectroscopic analysis, though he lacked the time to pursue its separation into its constituents. The heavy pair of [[samarium]] and europium were only removed in 1879 by [[Paul-Émile Lecoq de Boisbaudran]] and it was not until 1885 that [[Carl Auer von Welsbach]] separated didymium into praseodymium and neodymium.<ref name="Lost">{{cite book|ref=Fontani|last1=Fontani|first1=Marco|last2=Costa|first2=Mariagrazia|last3=Orna|first3=Virginia|title=The Lost Elements: The Periodic Table's Shadow Side|publisher=Oxford University Press|year=2014|url=https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA122|pages=122–123|isbn=978-0-19-938334-4}}</ref> Von Welsbach confirmed the separation by [[spectroscopic]] analysis, but the products were of relatively low purity. Since neodymium was a larger constituent of didymium than praseodymium, it kept the old name with disambiguation, while praseodymium was distinguished by the leek-green colour of its salts (Greek πρασιος, "leek green").<ref name="Greenwood1229">Greenwood and Earnshaw, p. 1229–32</ref> The composite nature of didymium had previously been suggested in 1882 by [[Bohuslav Brauner]], who did not experimentally pursue its separation.<ref name="Lost_p40">{{cite book|ref=Fontani|last1=Fontani|first1=Marco|last2=Costa|first2=Mariagrazia|last3=Orna|first3=Virginia|title=The Lost Elements: The Periodic Table's Shadow Side|url=https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA40|publisher=Oxford University Press|year=2014|page=40|isbn=978-0-19-938334-4}}</ref>
==Occurrence and production==
Praseodymium is not particularly rare, despite it being in the rare-earth metals, making up 9.2 mg/kg of the Earth's crust.<ref name=CRC97>Abundance of Elements in the Earth's Crust and in the Sea, ''CRC Handbook of Chemistry and Physics,'' 97th edition (2016–2017), p. 14-17</ref> Praseodymium's classification as a rare-earth metal comes from its rarity relative to "common earths" such as lime and magnesia, the few known minerals containing it for which extraction is commercially viable, as well as the length and complexity of extraction.<ref name="patnaik">{{cite book | last =Patnaik | first =Pradyot | date = 2003 | title =Handbook of Inorganic Chemical Compounds | publisher = McGraw-Hill | pages = 444–446| isbn =978-0-07-049439-8 | url= {{Google books |plainurl=yes |id=Xqj-TTzkvTEC |page=243 }} | access-date = 2009-06-06}}</ref> Although not particularly rare, praseodymium is never found as a dominant rare earth in praseodymium-bearing minerals. It is always preceded by cerium and lanthanum and usually also by neodymium.<ref>
{{cite web |url=https://www.mindat.org/ |title=Mindat.org |author=Hudson Institute of Mineralogy |date=1993–2018 |website=www.mindat.org |access-date=14 January 2018}}</ref>
[[File:Monazite acid cracking process.svg|frameless|center|730px]]
The Pr<sup>3+</sup> ion is similar in size to the early lanthanides of the cerium group (those from lanthanum up to [[samarium]] and [[europium]]) that immediately follow in the periodic table, and hence it tends to occur along with them in [[phosphate]], [[silicate]] and [[carbonate]] minerals, such as [[monazite]] (M<sup>III</sup>PO<sub>4</sub>) and [[bastnäsite]] (M<sup>III</sup>CO<sub>3</sub>F), where M refers to all the rare-earth metals except scandium and the radioactive [[promethium]] (mostly Ce, La, and Y, with somewhat less Nd and Pr).<ref name="Greenwood1229" /> Bastnäsite is usually lacking in [[thorium]] and the heavy lanthanides, and the purification of the light lanthanides from it is less involved. The ore, after being crushed and ground, is first treated with hot concentrated sulfuric acid, evolving carbon dioxide, [[hydrogen fluoride]], and [[silicon tetrafluoride]]. The product is then dried and leached with water, leaving the early lanthanide ions, including lanthanum, in solution.<ref name="Greenwood1229" />
The procedure for monazite, which usually contains all the rare earth, as well as thorium, is more involved. Monazite, because of its magnetic properties, can be separated by repeated electromagnetic separation. After separation, it is treated with hot concentrated sulfuric acid to produce water-soluble sulfates of rare earth. The acidic filtrates are partially neutralized with [[sodium hydroxide]] to pH 3–4, during which thorium precipitates as hydroxide and is removed. The solution is treated with [[ammonium oxalate]] to convert rare earth to their insoluble [[oxalate]]s, the oxalates are converted to oxides by annealing, and the oxides are dissolved in nitric acid. This last step excludes one of the main components, [[cerium]], whose oxide is insoluble in HNO<sub>3</sub>.<ref name="Patnaik">{{harvnb|Patnaik|2007|pp=[https://books.google.com/books?id=-CRRJBVv5d0C&pg=PA478 478–479]}}.</ref> Care must be taken when handling some of the residues as they contain [[radium-228|<sup>228</sup>Ra]], the daughter of <sup>232</sup>Th, which is a strong gamma emitter.<ref name="Greenwood1229" />
Praseodymium may then be separated from the other lanthanides via ion-exchange chromatography, or by using a solvent such as [[tributyl phosphate]] where the solubility of Ln<sup>3+</sup> increases as the atomic number increases. If ion-exchange chromatography is used, the mixture of lanthanides is loaded into one column of cation-exchange resin and Cu<sup>2+</sup> or Zn<sup>2+</sup> or Fe<sup>3+</sup> is loaded into the other. An aqueous solution of a complexing agent, known as the eluant (usually triammonium edtate), is passed through the columns, and Ln<sup>3+</sup> is displaced from the first column and redeposited in a compact band at the top of the column before being re-displaced by {{chem|NH|4|+}}. The [[Gibbs free energy]] of formation for Ln(edta·H) complexes increases along with the lanthanides by about one quarter from Ce<sup>3+</sup> to Lu<sup>3+</sup>, so that the Ln<sup>3+</sup> cations descend the development column in a band and are fractionated repeatedly, eluting from heaviest to lightest. They are then precipitated as their insoluble oxalates, burned to form the oxides, and then reduced to metals.<ref name="Greenwood1229" />
==Applications==
Leo Moser (not to be confused with [[Leo Moser|the mathematician of the same name]]), son of Ludwig Moser, founder of the [[Moser Glass]]works in what is now [[Karlovy Vary]] in the Czech Republic, investigated the use of praseodymium in glass coloration in the late 1920s, yielding a yellow-green glass given the name "Prasemit". However, at that time far cheaper colorants could give a similar color, so Prasemit was not popular, few pieces were made, and examples are now extremely rare. Moser also blended praseodymium with neodymium to produce "Heliolite" glass ("Heliolit" in [[German language|German]]),<!--http://books.google.de/books?id=36dRAAAAMAAJ&q=praseodymium+glass+moser&dq=praseodymium+glass+moser&hl=de&ei=Ptt0TLLYE5KHswalhr2IBg&sa=X&oi=book_result&ct=result&resnum=2&ved=0CD4Q6AEwAQ--> which was more widely accepted. The first enduring commercial use of purified praseodymium, which continues today, is in the form of a yellow-orange "Praseodymium Yellow" stain for ceramics, which is a solid solution in the [[zirconium(IV) silicate|zircon]] lattice. This stain has no hint of green in it; by contrast, at sufficiently high loadings, praseodymium glass is distinctly green rather than pure yellow.<ref>{{cite journal | last1 = Kreidl | first1 = Norbert J. | title = RARE EARTHS* | journal = Journal of the American Ceramic Society | volume = 25 | pages = 141–143 | date = 1942 | doi = 10.1111/j.1151-2916.1942.tb14363.x | issue = 5}}</ref>
Like many other lanthanides, praseodymium's shielded [[f-orbital]]s allow for long [[excited state]] lifetimes and high [[luminescence]] yields. Pr<sup>3+</sup> as a [[Doping (semiconductor)|dopant]] ion therefore sees many applications in [[optics]] and [[photonics]]. These include [[Pr:YLF laser|DPSS-lasers]], single-mode fiber [[optical amplifier]]s,<ref>{{cite journal|last1=Jha|first1=A.|last2=Naftaly|first2=M.|last3=Jordery|first3=S.|last4=Samson|first4=B. N.|last5=Taylor|first5=E. R.|last6=Hewak|first6=D.|last7=Payne|first7=D. N.|last8=Poulain|first8=M.|last9=Zhang|first9=G.|display-authors=4|date=1995|title=Design and fabrication of Pr3+-doped fluoride glass optical fibres for efficient 1.3 mu m amplifiers|url=https://eprints.soton.ac.uk/78174/1/918.pdf|journal=Pure and Applied Optics: Journal of the European Optical Society Part A|volume=4|issue=4|pages=417|bibcode=1995PApOp...4..417J|doi=10.1088/0963-9659/4/4/019}}</ref> fiber lasers,<ref>{{Cite journal|last1=Smart|first1=R.G.|last2=Hanna|first2=D.C.|last3=Tropper|first3=A.C.|last4=Davey|first4=S.T.|last5=Carter|first5=S.F.|last6=Szebesta|first6=D.|date=1991|title=Cw room temperature upconversion lasing at blue, green and red wavelengths in infrared-pumped Pr3+-doped fluoride fibre|url=https://digital-library.theiet.org/content/journals/10.1049/el_19910817|journal=Electronics Letters|language=en|volume=27|issue=14|pages=1307|doi=10.1049/el:19910817|bibcode=1991ElL....27.1307S}}</ref> [[upconverting nanoparticles]]<ref>{{Cite journal|last1=de Prinse|first1=Thomas J.|last2=Karami|first2=Afshin|last3=Moffatt|first3=Jillian E.|last4=Payten|first4=Thomas B.|last5=Tsiminis|first5=Georgios|last6=Teixeira|first6=Lewis Da Silva|last7=Bi|first7=Jingxiu|last8=Kee|first8=Tak W.|last9=Klantsataya|first9=Elizaveta|last10=Sumby|first10=Christopher J.|last11=Spooner|first11=Nigel A.|date=2021|title=Dual Laser Study of Non‐Degenerate Two Wavelength Upconversion Demonstrated in Sensitizer‐Free NaYF 4 :Pr Nanoparticles|url=https://onlinelibrary.wiley.com/doi/10.1002/adom.202001903|journal=Advanced Optical Materials|volume=9|issue=7|language=en|pages=2001903|doi=10.1002/adom.202001903|s2cid=234059121|issn=2195-1071|hdl=2440/139814|hdl-access=free}}</ref><ref>{{Cite journal|last1=Kolesov|first1=Roman|last2=Reuter|first2=Rolf|last3=Xia|first3=Kangwei|last4=Stöhr|first4=Rainer|last5=Zappe|first5=Andrea|last6=Wrachtrup|first6=Jörg|date=2011-10-31|title=Super-resolution upconversion microscopy of praseodymium-doped yttrium aluminum garnet nanoparticles|url=https://link.aps.org/doi/10.1103/PhysRevB.84.153413|journal=Physical Review B|language=en|volume=84|issue=15|pages=153413|doi=10.1103/PhysRevB.84.153413|bibcode=2011PhRvB..84o3413K|issn=1098-0121}}</ref> as well as activators in red, green, blue, and ultraviolet phosphors.<ref name="Ullmann" /> Silicate crystals doped with praseodymium ions have also been used to [[slow light|slow a light pulse]] down to a few hundred meters per second.<ref name="ANUPressStopLight">{{cite web|title=ANU team stops light in quantum leap|url=http://info.anu.edu.au/ovc/Media/Media_Releases/2005/August/290805_stop_light|access-date=18 May 2009}}</ref>
As the lanthanides are so similar, praseodymium can substitute for most other lanthanides without significant loss of function, and indeed many applications such as [[mischmetal]] and [[ferrocerium]] alloys involve variable mixes of several lanthanides, including small quantities of praseodymium. The following more modern applications involve praseodymium specifically or at least praseodymium in a small subset of the lanthanides:<ref name="Ullmann" />
* In combination with neodymium, another rare-earth element, praseodymium is used to create high-power magnets notable for their strength and durability.<ref name="IAMGOLD">[http://www.iamgold.com/files/REE101_April_2012.pdf Rare Earth Elements 101] {{webarchive|url=https://web.archive.org/web/20131122140504/http://www.iamgold.com/files/REE101_April_2012.pdf |date=2013-11-22 }}, IAMGOLD Corporation, April 2012, pp. 5, 7.</ref> In general, most alloys of the cerium-group rare earths ([[lanthanum]] through [[samarium]]) with 3d [[transition metal]]s give extremely stable magnets that are often used in small equipment, such as motors, printers, watches, headphones, loudspeakers, and magnetic storage.<ref name="Ullmann">{{Ullmann|volume=31|page=183–227|last1=McGill|first1=Ian|contribution=Rare Earth Elements|doi=10.1002/14356007.a22_607}}</ref>
*Praseodymium–[[nickel]] intermetallic (PrNi<sub>5</sub>) has such a strong [[Magnetic refrigeration#The magnetocaloric effect|magnetocaloric effect]] that it has allowed scientists to approach within one thousandth of a degree of [[absolute zero]].<ref name="Emsley423" />
* As an [[alloy]]ing agent with [[magnesium]] to create high-strength metals that are used in [[aircraft engine]]s; [[yttrium]] and [[neodymium]] are also viable substitutes.<ref>{{cite book| first = L. L. |last = Rokhlin | title = Magnesium alloys containing rare earth metals: structure and properties| publisher = CRC Press| date = 2003| isbn =978-0-415-28414-1}}</ref><ref>{{cite journal | last1 = Suseelan Nair | first1 = K. | last2 = Mittal | first2 = M. C. | title = Rare Earths in Magnesium Alloys | journal = Materials Science Forum | volume = 30 | pages = 89–104 | date = 1988 | doi = 10.4028/www.scientific.net/MSF.30.89| s2cid = 136992837 }}</ref>
* Praseodymium is present in the rare-earth mixture whose fluoride forms the core of [[carbon arc light]]s, which are used in the [[movie studio|motion picture industry]] for [[studio]] lighting and [[Image projector|projector]] lights.<ref name="Emsley423">Emsley, pp. 423–5</ref>
* Praseodymium [[chemical compound|compounds]] give [[glass]]es, [[vitreous enamel|enamels]] and ceramics a [[yellow]] color.<ref name="CRC" /><ref name="Ullmann" />
* Praseodymium is a component of [[didymium]] glass, which is used to make certain types of [[welding|welder]]'s and [[glass blowing|glass blower]]'s [[goggles]].<ref name="CRC" />
* Praseodymium oxide in solid solution with [[ceria]] or [[ceria-zirconia]] has been used as an [[oxidation]] [[catalyst]].<ref>{{cite journal| doi = 10.1021/jp0768524| title = Nanostructured Praseodymium Oxide: Preparation, Structure, and Catalytic Properties| date = 2008| display-authors = 4| author = Borchert, Y.| author2 = Sonstrom, P.| author3 = Wilhelm, M.| author4 = Borchert, H.| author5 = Baumer, M.| journal = Journal of Physical Chemistry C| volume = 112| pages = 3054| issue = 8}}</ref>
Due to its role in permanent magnets used for wind turbines, it has been argued that praseodymium will be one of the main objects of geopolitical competition in a world running on renewable energy. However, this perspective has been criticized for failing to recognize that most wind turbines do not use permanent magnets and for underestimating the power of economic incentives for expanded production.<ref>{{Cite journal|last=Overland|first=Indra|date=2019-03-01|title=The geopolitics of renewable energy: Debunking four emerging myths|journal=Energy Research & Social Science|volume=49|pages=36–40|doi=10.1016/j.erss.2018.10.018|issn=2214-6296|doi-access=free}}</ref><ref name="Klinger">{{cite book |last1=Klinger |first1=Julie Michelle |title=Rare earth frontiers : from terrestrial subsoils to lunar landscapes |date=2017 |publisher=Cornell University Press |location=Ithaca, NY |isbn=978-1501714603 |jstor=10.7591/j.ctt1w0dd6d }}</ref>
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}}
==Biological role and precautions==
The early lanthanides have been found to be essential to some [[methanotrophic]] bacteria living in [[Mudpot|volcanic mudpots]], such as ''[[Methylacidiphilum fumariolicum]]'': lanthanum, cerium, praseodymium, and neodymium are about equally effective.<ref>{{cite journal |doi=10.1111/1462-2920.12249 |pmid=24034209 |title=Rare earth metals are essential for methanotrophic life in volcanic mudpots |date=2013 |last1=Pol |first1=Arjan |last2=Barends |first2=Thomas R. M. |last3=Dietl |first3=Andreas |last4=Khadem |first4=Ahmad F. |last5=Eygensteyn |first5=Jelle |last6=Jetten |first6=Mike S. M. |last7=Op Den Camp |first7=Huub J. M. |journal=Environmental Microbiology |volume=16 |issue=1 |pages=255–64}}</ref><ref>{{cite journal | last1=Kang | first1=L. | last2=Shen | first2=Z. | last3=Jin | first3=C. | title=Neodymium cations Nd<sup>3+</sup> were transported to the interior of ''Euglena gracilis'' | issue=277 | journal=Chin. Sci. Bull. | volume=45 | pages=585–592 | date=2000 | doi=10.1007/BF02886032| bibcode=2000ChSBu..45..585K | s2cid=95983365 }}</ref> Praseodymium is otherwise not known to have a biological role in any other organisms, but it is not very toxic either. Intravenous injection of rare earths into animals has been known to impair liver function, but the main side effects from inhalation of rare-earth oxides in humans come from radioactive [[thorium]] and [[uranium]] impurities.<ref name="Ullmann" />
{{clear}}
==Notes==
{{Notelist}}
==References==
{{Reflist|30em}}
==Bibliography==
*{{cite book|author=Emsley, John|title=Nature's Building Blocks: An A-Z Guide to the Elements|date=2011|publisher=[[Oxford University Press]]|isbn=978-0-19-960563-7}}
*{{Greenwood&Earnshaw2nd}}
== Further reading ==
* R. J. Callow, ''The Industrial Chemistry of the Lanthanons, Yttrium, Thorium, and Uranium'', Pergamon Press, 1967.
* Bouhani, H (2020). "Engineering the magnetocaloric properties of PrVO3 epitaxial oxide thin films by strain effects". Applied Physics Letters. 117 (7). arXiv:2008.09193. doi:10.1063/5.0021031.
== External links ==
{{Commons|Praseodymium}}
{{Wiktionary|praseodymium}}
* [http://www.webelements.com/webelements/elements/text/Pr/index.html WebElements.com—Praseodymium]
* [http://education.jlab.org/itselemental/ele059.html It's Elemental—The Element Praseodymium]
{{clear}}
{{Periodic table (navbox)}}
{{Praseodymium compounds}}
{{Authority control}}
[[Category:Praseodymium| ]]
[[Category:Chemical elements]]
[[Category:Chemical elements with double hexagonal close-packed structure]]
[[Category:Lanthanides]]
[[Category:Reducing agents]]' |
Parsed HTML source of the new revision (new_html) | '<div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><p class="mw-empty-elt">
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<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Chemical element, symbol Pr and atomic number 59</div><style data-mw-deduplicate="TemplateStyles:r1218072481">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}body.skin-minerva .mw-parser-output .infobox-header,body.skin-minerva .mw-parser-output .infobox-subheader,body.skin-minerva .mw-parser-output .infobox-above,body.skin-minerva .mw-parser-output .infobox-title,body.skin-minerva .mw-parser-output .infobox-image,body.skin-minerva .mw-parser-output .infobox-full-data,body.skin-minerva .mw-parser-output .infobox-below{text-align:center}html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data div{background:#1f1f23!important;color:#f8f9fa}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data div{background:#1f1f23!important;color:#f8f9fa}}</style><style data-mw-deduplicate="TemplateStyles:r1158442001">body.skin-minerva .mw-parser-output .infobox-full-data>.wikitable,body.skin-minerva .mw-parser-output .infobox .periodictable{display:table}body.skin-minerva .mw-parser-output .infobox-full-data{width:calc(100% - 20px)}body.skin-minerva .mw-parser-output .infobox-full-data>div{max-width:100%;overflow:auto}body.skin-minerva .mw-parser-output .infobox caption{display:table-caption}</style><table class="infobox"><caption class="infobox-title"><span class="nowrap">Praseodymium, <sub>59</sub>Pr</span></caption><tbody><tr><td colspan="2" class="infobox-image"><span class="mw-default-size" typeof="mw:File/Frameless"><a href="/info/en/?search=File:Praseodymium.jpg" class="mw-file-description"><img src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Praseodymium.jpg/220px-Praseodymium.jpg" decoding="async" width="220" height="220" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Praseodymium.jpg/330px-Praseodymium.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Praseodymium.jpg/440px-Praseodymium.jpg 2x" data-file-width="848" data-file-height="848" /></a></span></td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Praseodymium</th></tr><tr><th scope="row" class="infobox-label">Pronunciation</th><td class="infobox-data"><span class="rt-commentedText nowrap"><span class="IPA nopopups noexcerpt" lang="en-fonipa"><a href="/info/en/?search=Help:IPA/English" title="Help:IPA/English">/<span style="border-bottom:1px dotted"><span title="/ˌ/: secondary stress follows">ˌ</span><span title="'p' in 'pie'">p</span><span title="'r' in 'rye'">r</span><span title="/eɪ/: 'a' in 'face'">eɪ</span><span title="'z' in 'zoom'">z</span><span title="/iː/: 'ee' in 'fleece'">iː</span><span title="/ə/: 'a' in 'about'">ə</span><span title="/ˈ/: primary stress follows">ˈ</span><span title="'d' in 'dye'">d</span><span title="/ɪ/: 'i' in 'kit'">ɪ</span><span title="'m' in 'my'">m</span><span title="/i/: 'y' in 'happy'">i</span><span title="/ə/: 'a' in 'about'">ə</span><span title="'m' in 'my'">m</span></span>/</a></span></span><sup id="cite_ref-1" class="reference"><a href="#cite_note-1">[1]</a></sup> <wbr />​<span class="nowrap">(<a href="/info/en/?search=Help:Pronunciation_respelling_key" title="Help:Pronunciation respelling key"><i title="English pronunciation respelling"><span style="font-size:90%">PRAY</span>-zee-ə-<span style="font-size:90%">DIM</span>-ee-əm</i></a>)</span></td></tr><tr><th scope="row" class="infobox-label">Appearance</th><td class="infobox-data">grayish white</td></tr><tr><td colspan="2" class="infobox-full-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1218072481"></td></tr><tr><th colspan="2" class="infobox-header" style="text-align: left; color:inherit; background: transparant;"><a href="/info/en/?search=Standard_atomic_weight" title="Standard atomic weight">Standard atomic weight</a> <style data-mw-deduplicate="TemplateStyles:r886047488">.mw-parser-output .nobold{font-weight:normal}</style><span class="nobold"><i>A</i><sub>r</sub>°(Pr)</span></th></tr><tr><th scope="row" class="infobox-label"></th><td class="infobox-data"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style><div class="plainlist"><ul><li><span class="nowrap"><span data-sort-value="7002140907660000000♠"></span>140.907<span style="margin-left:.25em;">66</span><span style="margin-left:0.3em;margin-right:0.15em;">±</span>0.000<span style="margin-left:.25em;">01</span></span><sup id="cite_ref-2" class="reference"><a href="#cite_note-2">[2]</a></sup></li><li><span class="nowrap"><span data-sort-value="7002140910000000000♠"></span>140.91<span style="margin-left:0.3em;margin-right:0.15em;">±</span>0.01</span> (<a href="/info/en/?search=Standard_atomic_weight#Abridged_atomic_weight" title="Standard atomic weight">abridged</a>)<sup id="cite_ref-CIAAW2021_3-0" class="reference"><a href="#cite_note-CIAAW2021-3">[3]</a></sup></li></ul></div></td></tr><tr style="display:none"><td colspan="2">
</td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Praseodymium in the <a href="/info/en/?search=Periodic_table" title="Periodic table">periodic table</a></th></tr><tr><td colspan="2" class="infobox-full-data">
<table class="wikitable" style="text-align:center; width:100%; margin:0; background:#f8f8f8;">
<tbody><tr>
<td>
<table class="periodictable" style="margin:0 auto">
<tbody><tr>
<td style="border:none; width:5px"><div style="background-color:transparent; margin:0; padding:0; text-align:center; border:none;">
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<tbody><tr>
<td style="border:none;padding:0;"><a href="/info/en/?search=Hydrogen" title="Hydrogen"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Hydrogen</span></a>
</td>
<td colspan="30" style="border:none;padding:0;">
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Helium" title="Helium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Helium</span></a>
</td></tr>
<tr>
<td style="border:none;padding:0;"><a href="/info/en/?search=Lithium" title="Lithium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Lithium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Beryllium" title="Beryllium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Beryllium</span></a>
</td>
<td colspan="24" style="border:none;padding:0;">
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Boron" title="Boron"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Boron</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Carbon" title="Carbon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Carbon</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Nitrogen" title="Nitrogen"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Nitrogen</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Oxygen" title="Oxygen"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Oxygen</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Fluorine" title="Fluorine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Fluorine</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Neon" title="Neon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Neon</span></a>
</td></tr>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Sodium" title="Sodium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Sodium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Magnesium" title="Magnesium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Magnesium</span></a>
</td>
<td colspan="24" style="border:none;padding:0;">
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Aluminium" title="Aluminium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Aluminium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Silicon" title="Silicon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Silicon</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Phosphorus" title="Phosphorus"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Phosphorus</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Sulfur" title="Sulfur"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Sulfur</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Chlorine" title="Chlorine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Chlorine</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Argon" title="Argon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Argon</span></a>
</td></tr>
<tr>
<td style="border:none;padding:0;"><a href="/info/en/?search=Potassium" title="Potassium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Potassium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Calcium" title="Calcium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Calcium</span></a>
</td>
<td colspan="14" style="border:none;padding:0;">
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Scandium" title="Scandium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Scandium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Titanium" title="Titanium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Titanium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Vanadium" title="Vanadium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Vanadium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Chromium" title="Chromium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Chromium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Manganese" title="Manganese"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Manganese</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Iron" title="Iron"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Iron</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Cobalt" title="Cobalt"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Cobalt</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Nickel" title="Nickel"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Nickel</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Copper" title="Copper"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Copper</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Zinc" title="Zinc"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Zinc</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Gallium" title="Gallium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Gallium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Selenium" title="Selenium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Selenium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Bromine" title="Bromine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Bromine</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Krypton" title="Krypton"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Krypton</span></a>
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<tr>
<td style="border:none;padding:0;"><a href="/info/en/?search=Rubidium" title="Rubidium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Rubidium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Strontium" title="Strontium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Strontium</span></a>
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<td style="border:none;padding:0;; width:0;">
</td>
<td colspan="13" style="border:none;padding:0;">
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Yttrium" title="Yttrium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Yttrium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Zirconium" title="Zirconium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Zirconium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Niobium" title="Niobium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Niobium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Molybdenum" title="Molybdenum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Molybdenum</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Rhodium" title="Rhodium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Rhodium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Palladium" title="Palladium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Palladium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Silver" title="Silver"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Silver</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Cadmium" title="Cadmium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Cadmium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Indium" title="Indium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Indium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Tin" title="Tin"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Tin</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Antimony" title="Antimony"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Antimony</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Tellurium" title="Tellurium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Tellurium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Iodine" title="Iodine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Iodine</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Xenon" title="Xenon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Xenon</span></a>
</td></tr>
<tr style="border:none;padding:0;">
<td style="border:none;padding:0;"><a href="/info/en/?search=Caesium" title="Caesium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Caesium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Barium" title="Barium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Barium</span></a>
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<td style="border:none;padding:0;"><a href="/info/en/?search=Lanthanum" title="Lanthanum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Lanthanum</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Cerium" title="Cerium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Cerium</span></a>
</td>
<td style="border:none;padding:0;"><a class="mw-selflink selflink"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99; border:1px solid black; box-sizing: border-box;;">Praseodymium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Neodymium" title="Neodymium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Neodymium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Promethium" title="Promethium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Promethium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Samarium" title="Samarium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Samarium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Europium" title="Europium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Europium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Gadolinium" title="Gadolinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Gadolinium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Terbium" title="Terbium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Terbium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Dysprosium" title="Dysprosium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Dysprosium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Holmium" title="Holmium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Holmium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Erbium" title="Erbium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Erbium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Thulium" title="Thulium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Thulium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Ytterbium" title="Ytterbium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Ytterbium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Lutetium" title="Lutetium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Lutetium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Hafnium" title="Hafnium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Hafnium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Tantalum" title="Tantalum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Tantalum</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Tungsten" title="Tungsten"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Tungsten</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Rhenium" title="Rhenium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Rhenium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Osmium" title="Osmium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Osmium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Iridium" title="Iridium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Iridium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Platinum" title="Platinum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Platinum</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Gold" title="Gold"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Gold</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Mercury_(element)" title="Mercury (element)"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Mercury (element)</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Thallium" title="Thallium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Thallium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Lead" title="Lead"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Lead</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Bismuth" title="Bismuth"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Bismuth</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Polonium" title="Polonium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Polonium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Astatine" title="Astatine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Astatine</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Radon" title="Radon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Radon</span></a>
</td></tr>
<tr>
<td style="border:none;padding:0;"><a href="/info/en/?search=Francium" title="Francium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Francium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Radium" title="Radium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Radium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Actinium" title="Actinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Actinium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Thorium" title="Thorium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Thorium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Protactinium" title="Protactinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Protactinium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Uranium" title="Uranium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Uranium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Neptunium" title="Neptunium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Neptunium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Plutonium" title="Plutonium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Plutonium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Americium" title="Americium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Americium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Curium" title="Curium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Curium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Berkelium" title="Berkelium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Berkelium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Californium" title="Californium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Californium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Einsteinium" title="Einsteinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Einsteinium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Fermium" title="Fermium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Fermium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Mendelevium" title="Mendelevium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Mendelevium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Nobelium" title="Nobelium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Nobelium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Lawrencium" title="Lawrencium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Lawrencium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Rutherfordium" title="Rutherfordium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Rutherfordium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Dubnium" title="Dubnium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Dubnium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Seaborgium" title="Seaborgium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Seaborgium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Bohrium" title="Bohrium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Bohrium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Hassium" title="Hassium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Hassium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Meitnerium" title="Meitnerium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Meitnerium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Darmstadtium" title="Darmstadtium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Darmstadtium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Roentgenium" title="Roentgenium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Roentgenium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Copernicium" title="Copernicium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Copernicium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Nihonium" title="Nihonium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Nihonium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Flerovium" title="Flerovium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Flerovium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Moscovium" title="Moscovium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Moscovium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Livermorium" title="Livermorium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Livermorium</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Tennessine" title="Tennessine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Tennessine</span></a>
</td>
<td style="border:none;padding:0;"><a href="/info/en/?search=Oganesson" title="Oganesson"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Oganesson</span></a>
</td></tr></tbody></table>
</div>
</td>
<td style="vertical-align:middle; text-align:center; font-size:90%; line-height:100%; width:10px; border:none;">–<br />↑<br /><strong>Pr</strong><br />↓<br /><a href="/info/en/?search=Protactinium" title="Protactinium">Pa</a>
</td></tr>
<tr>
<td colspan="2" class="nowrap" style="text-align:center; font-size:90%; line-height:100%; padding-top:0; padding-bottom:1px; border:none;"><a href="/info/en/?search=Cerium" title="Cerium">cerium</a> ← <strong>praseodymium</strong> → <a href="/info/en/?search=Neodymium" title="Neodymium">neodymium</a>
</td></tr></tbody></table>
</td></tr></tbody></table></td></tr><tr><th scope="row" class="infobox-label"><span class="nowrap"><a href="/info/en/?search=Atomic_number" title="Atomic number">Atomic number</a> <span style="font-weight:normal;">(<i>Z</i>)</span></span></th><td class="infobox-data">59</td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Group_(periodic_table)" title="Group (periodic table)">Group</a></th><td class="infobox-data"><a href="/info/en/?search=F-block_groups" class="mw-redirect" title="F-block groups">f-block groups</a> (no number)</td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Period_(periodic_table)" title="Period (periodic table)">Period</a></th><td class="infobox-data"><a href="/info/en/?search=Period_6_element" title="Period 6 element">period 6</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Block_(periodic_table)" title="Block (periodic table)">Block</a></th><td class="infobox-data"><span title="color legend: f-block" style="display:inline-block; vertical-align:middle; width:6px; height:8px; border:1px solid black; background:#9bff99"> </span> <a href="/info/en/?search=Block_(periodic_table)#f-block" title="Block (periodic table)">f-block</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Electron_configuration" title="Electron configuration">Electron configuration</a></th><td class="infobox-data">[<a href="/info/en/?search=Xenon" title="Xenon">Xe</a>] 4f<sup>3</sup> 6s<sup>2</sup></td></tr><tr><th scope="row" class="infobox-label">Electrons per shell</th><td class="infobox-data">2, 8, 18, 21, 8, 2</td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Physical properties</th></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Phase_(matter)" title="Phase (matter)">Phase</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886047488"><span class="nobold">at <span title="STP: standard temperature and pressure: 0 °C and 101.325 kPa"><a href="/info/en/?search=Standard_temperature_and_pressure" title="Standard temperature and pressure">STP</a></span></span></th><td class="infobox-data"><a href="/info/en/?search=Solid" title="Solid">solid</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Melting_point" title="Melting point">Melting point</a></th><td class="infobox-data">1204 <a href="/info/en/?search=Kelvin" title="Kelvin">K</a> ​(931 °C, ​1708 °F)<sup id="cite_ref-Arblaster_2018_4-0" class="reference"><a href="#cite_note-Arblaster_2018-4">[4]</a></sup> </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Boiling_point" title="Boiling point">Boiling point</a></th><td class="infobox-data">3403 K ​(3130 °C, ​5666 °F) </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Density" title="Density">Density</a><span style="font-weight:normal;"> (at 20° C)</span></th><td class="infobox-data">6.773 g/cm<sup>3</sup> <sup id="cite_ref-Arblaster_2018_4-1" class="reference"><a href="#cite_note-Arblaster_2018-4">[4]</a></sup></td></tr><tr><th scope="row" class="infobox-label"><span style="font-weight:normal;">when liquid (at <a href="/info/en/?search=Melting_point" title="Melting point">m.p.</a>)</span></th><td class="infobox-data">6.50 g/cm<sup>3</sup> </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Enthalpy_of_fusion" title="Enthalpy of fusion">Heat of fusion</a></th><td class="infobox-data">6.89 <a href="/info/en/?search=Kilojoule_per_mole" class="mw-redirect" title="Kilojoule per mole">kJ/mol</a> </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Enthalpy_of_vaporization" title="Enthalpy of vaporization">Heat of vaporization</a></th><td class="infobox-data">331 kJ/mol </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Molar_heat_capacity" title="Molar heat capacity">Molar heat capacity</a></th><td class="infobox-data">27.20 J/(mol·K) </td></tr><tr><td colspan="2" class="infobox-full-data"><a href="/info/en/?search=Vapor_pressure" title="Vapor pressure"><b>Vapor pressure</b></a><div style="position:relative; margin:0 auto; padding:0; text-align:initial; width:-moz-fit-content;width:-webkit-fit-content;width:fit-content;">
<table class="wikitable" style="text-align:center; font-size:90%; border-collapse:collapse; margin:0">
<tbody><tr>
<th><abbr title="Pressure"><i>P</i></abbr> <span style="font-weight:normal;">(Pa)</span>
</th>
<th>1
</th>
<th>10
</th>
<th>100
</th>
<th>1 k
</th>
<th>10 k
</th>
<th>100 k
</th></tr>
<tr>
<th>at <abbr title="Temperature"><i>T</i></abbr> <span style="font-weight:normal;">(K)</span>
</th>
<td>1771
</td>
<td>1973
</td>
<td>(2227)
</td>
<td>(2571)
</td>
<td>(3054)
</td>
<td>(3779)
</td></tr></tbody></table>
</div></td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Atomic properties</th></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Oxidation_state" title="Oxidation state">Oxidation states</a></th><td class="infobox-data">0,<sup id="cite_ref-Cloke1993_5-0" class="reference"><a href="#cite_note-Cloke1993-5">[5]</a></sup> +1,<sup id="cite_ref-6" class="reference"><a href="#cite_note-6">[6]</a></sup> +2, <span style="font-size:112%;"><b>+3</b></span>, +4, +5 (a mildly <a href="/info/en/?search=Base_(chemistry)" title="Base (chemistry)">basic</a> oxide)</td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Electronegativity" title="Electronegativity">Electronegativity</a></th><td class="infobox-data">Pauling scale: 1.13 </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Ionization_energy" title="Ionization energy">Ionization energies</a></th><td class="infobox-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li>1st: 527 kJ/mol </li><li>2nd: 1020 kJ/mol </li><li>3rd: 2086 kJ/mol </li><li> </li></ul></div></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Atomic_radius" title="Atomic radius">Atomic radius</a></th><td class="infobox-data">empirical: 182 <a href="/info/en/?search=Picometre" title="Picometre">pm</a> </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Covalent_radius" title="Covalent radius">Covalent radius</a></th><td class="infobox-data">203±7 pm </td></tr><tr><td colspan="2" class="infobox-full-data"><figure class="mw-default-size mw-halign-center" typeof="mw:File/Frameless"><a href="/info/en/?search=File:Praseodymium_spectrum_visible.png" class="mw-file-description"><img alt="Color lines in a spectral range" src="https://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Praseodymium_spectrum_visible.png/240px-Praseodymium_spectrum_visible.png" decoding="async" width="240" height="41" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Praseodymium_spectrum_visible.png/360px-Praseodymium_spectrum_visible.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Praseodymium_spectrum_visible.png/480px-Praseodymium_spectrum_visible.png 2x" data-file-width="7430" data-file-height="1280" /></a><figcaption></figcaption></figure><strong><a href="/info/en/?search=Spectral_line" title="Spectral line">Spectral lines</a> of praseodymium</strong></td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Other properties</th></tr><tr><th scope="row" class="infobox-label">Natural occurrence</th><td class="infobox-data"><a href="/info/en/?search=Primordial_nuclide" title="Primordial nuclide">primordial</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Crystal_structure" title="Crystal structure">Crystal structure</a></th><td class="infobox-data"> ​<a href="/info/en/?search=Close-packing_of_equal_spheres" title="Close-packing of equal spheres">double hexagonal close-packed</a> (dhcp) (<a href="/info/en/?search=Pearson_symbol" title="Pearson symbol">hP4</a>)</td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Lattice_constant" title="Lattice constant">Lattice constants</a></th><td class="infobox-data"><div style="float:right;"><span class="mw-default-size" typeof="mw:File/Frameless"><a href="/info/en/?search=File:Hexagonal.svg" class="mw-file-description"><img alt="Double hexagonal close packed crystal structure for praseodymium" src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c2/Hexagonal.svg/50px-Hexagonal.svg.png" decoding="async" width="50" height="52" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c2/Hexagonal.svg/75px-Hexagonal.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c2/Hexagonal.svg/100px-Hexagonal.svg.png 2x" data-file-width="295" data-file-height="304" /></a></span></div><i>a</i> = 0.36723 nm<br /><i>c</i> = 1.18328 nm (at 20 °C)<sup id="cite_ref-Arblaster_2018_4-2" class="reference"><a href="#cite_note-Arblaster_2018-4">[4]</a></sup></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Coefficient_of_thermal_expansion" class="mw-redirect" title="Coefficient of thermal expansion">Thermal expansion</a></th><td class="infobox-data"><span class="nowrap"><span data-sort-value="6994450000000000000♠"></span>4.5<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−6</sup></span>/K (at 20 °C)<sup id="cite_ref-Arblaster_2018_4-3" class="reference"><a href="#cite_note-Arblaster_2018-4">[4]</a></sup><sup id="cite_ref-7" class="reference"><a href="#cite_note-7">[a]</a></sup></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Thermal_conductivity" class="mw-redirect" title="Thermal conductivity">Thermal conductivity</a></th><td class="infobox-data">12.5 W/(m⋅K) </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Electrical_resistivity_and_conductivity" title="Electrical resistivity and conductivity">Electrical resistivity</a></th><td class="infobox-data">poly: 0.700 µΩ⋅m (at <abbr title="room temperature">r.t.</abbr>)</td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Magnetism" title="Magnetism">Magnetic ordering</a></th><td class="infobox-data"><a href="/info/en/?search=Paramagnetic" class="mw-redirect" title="Paramagnetic">paramagnetic</a><sup id="cite_ref-jackson_8-0" class="reference"><a href="#cite_note-jackson-8">[7]</a></sup> </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Magnetic_susceptibility" title="Magnetic susceptibility">Molar magnetic susceptibility</a></th><td class="infobox-data"><span class="nowrap"><span data-sort-value="6997501000000000000♠"></span>+5<span style="margin-left:.25em;">010</span>.0<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−6</sup></span> cm<sup>3</sup>/mol (293 K)<sup id="cite_ref-9" class="reference"><a href="#cite_note-9">[8]</a></sup></td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Young%27s_modulus" title="Young's modulus">Young's modulus</a></th><td class="infobox-data">37.3 GPa </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Shear_modulus" title="Shear modulus">Shear modulus</a></th><td class="infobox-data">14.8 GPa </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Bulk_modulus" title="Bulk modulus">Bulk modulus</a></th><td class="infobox-data">28.8 GPa </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Speed_of_sound" title="Speed of sound">Speed of sound</a>  <span style="font-weight:normal;">thin rod</span></th><td class="infobox-data">2280 m/s (at 20 °C) </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Poisson%27s_ratio" title="Poisson's ratio">Poisson ratio</a></th><td class="infobox-data">0.281 </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Vickers_hardness_test" title="Vickers hardness test">Vickers hardness</a></th><td class="infobox-data">250–745 MPa </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Brinell_hardness_test" class="mw-redirect" title="Brinell hardness test">Brinell hardness</a></th><td class="infobox-data">250–640 MPa </td></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=CAS_Registry_Number" title="CAS Registry Number">CAS Number</a></th><td class="infobox-data">7440-10-0 </td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">History</th></tr><tr><th scope="row" class="infobox-label"><a href="/info/en/?search=Timeline_of_chemical_element_discoveries" class="mw-redirect" title="Timeline of chemical element discoveries">Discovery</a></th><td class="infobox-data"><a href="/info/en/?search=Carl_Auer_von_Welsbach" title="Carl Auer von Welsbach">Carl Auer von Welsbach</a><span class="nowrap"> (1885)</span></td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99"><a href="/info/en/?search=Isotopes_of_praseodymium" title="Isotopes of praseodymium">Isotopes of praseodymium</a><span style="float:right; padding-right: 0.2em;"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output 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class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/info/en/?search=Template:Infobox_praseodymium_isotopes" title="Template:Infobox praseodymium isotopes"><abbr title="View this template">v</abbr></a></li><li class="nv-edit"><a href="/info/en/?search=Special:EditPage/Template:Infobox_praseodymium_isotopes" title="Special:EditPage/Template:Infobox praseodymium isotopes"><abbr title="Edit this template">e</abbr></a></li></ul></div></span></th></tr><tr><td colspan="2" class="infobox-full-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1218072481"></td></tr><tr><td colspan="2" class="infobox-full-data">
<table class="wikitable" style="text-align: center; vertical-align: middle; width: 100%; border-collapse: collapse; margin: 0; padding: 0;">
<tbody><tr>
<th colspan="3">Main isotopes<sup id="cite_ref-NUBASE2020_10-0" class="reference"><a href="#cite_note-NUBASE2020-10">[9]</a></sup>
</th>
<th colspan="2"><a href="/info/en/?search=Radioactive_decay" title="Radioactive decay">Decay</a>
</th></tr>
<tr>
<th>
</th>
<th style="padding: 0.1em;"><a href="/info/en/?search=Natural_abundance" title="Natural abundance">abun­dance</a>
</th>
<th style="padding: 0.1em;"><a href="/info/en/?search=Half-life" title="Half-life">half-life</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886047488"><span class="nobold">(<i>t</i><sub>1/2</sub>)</span>
</th>
<th style="padding: 0.1em;"><a href="/info/en/?search=Radioactive_decay#Types_of_decay" title="Radioactive decay">mode</a>
</th>
<th style="padding: 0.1em;"><a href="/info/en/?search=Decay_product" title="Decay product">pro­duct</a>
</th></tr>
<tr>
<th rowspan="1" style="vertical-align: top;"><sup>141</sup>Pr
</th>
<td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">100%
</td>
<td rowspan="1" colspan="3" style="vertical-align: top; text-align: left;"><a href="/info/en/?search=Stable_isotope" class="mw-redirect" title="Stable isotope">stable</a>
</td></tr>
<tr>
<th rowspan="2" style="vertical-align: top;"><sup>142</sup>Pr
</th>
<td rowspan="2" colspan="1" style="vertical-align: top; text-align: center;"><a href="/info/en/?search=Synthetic_radioisotope" title="Synthetic radioisotope">synth</a>
</td>
<td rowspan="2" colspan="1" style="vertical-align: top; text-align: right;"><span class="nowrap"><span data-sort-value="7004688320000000000♠"></span>19.12 h</span>
</td>
<td style="text-align: left; vertical-align: top;"><span style="float: left; font-size: 115%; padding: 0;"><a href="/info/en/?search=Beta_minus_decay" class="mw-redirect" title="Beta minus decay">β<sup>−</sup></a></span><span style="float: right; padding-left: 0.2em;"></span>
</td>
<td style="text-align: right; vertical-align: middle;"><a href="/info/en/?search=Neodymium-142" class="mw-redirect" title="Neodymium-142"><sup>142</sup>Nd</a>
</td></tr>
<tr>
<td style="text-align: left; vertical-align: top;"><span style="float: left; font-size: 115%; padding: 0;"><a href="/info/en/?search=Electron_capture" title="Electron capture">ε</a></span><span style="float: right; padding-left: 0.2em;"></span>
</td>
<td style="text-align: right; vertical-align: middle;"><a href="/info/en/?search=Cerium-142" class="mw-redirect" title="Cerium-142"><sup>142</sup>Ce</a>
</td></tr>
<tr>
<th rowspan="1" style="vertical-align: top;"><sup>143</sup>Pr
</th>
<td rowspan="1" colspan="1" style="vertical-align: top; text-align: center;">synth
</td>
<td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;"><span class="nowrap"><span data-sort-value="7006117244800000000♠"></span>13.57 d</span>
</td>
<td style="text-align: left; vertical-align: top;"><span style="float: left; font-size: 115%; padding: 0;">β<sup>−</sup></span><span style="float: right; padding-left: 0.2em;"></span>
</td>
<td style="text-align: right; vertical-align: middle;"><a href="/info/en/?search=Neodymium-143" class="mw-redirect" title="Neodymium-143"><sup>143</sup>Nd</a>
</td></tr></tbody></table></td></tr><tr style="display:none"><td colspan="2">
</td></tr><tr><td colspan="2" class="infobox-below noprint" style="color:inherit; background:#9bff99"><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="https://upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/info/en/?search=Category:Praseodymium" title="Category:Praseodymium">Category: Praseodymium</a><br /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1063604349"><div class="navbar plainlinks hlist"><ul><li class="nv-view"><a href="/info/en/?search=Template:Infobox_praseodymium" title="Template:Infobox praseodymium"><span title="View this template">view</span></a></li><li class="nv-talk"><a href="/info/en/?search=Template_talk:Infobox_praseodymium" title="Template talk:Infobox praseodymium"><span title="Discuss this template">talk</span></a></li><li class="nv-edit"><a href="/info/en/?search=Special:EditPage/Template:Infobox_praseodymium" title="Special:EditPage/Template:Infobox praseodymium"><span title="Edit this template">edit</span></a></li></ul></div> | <a href="/info/en/?search=List_of_data_references_for_chemical_elements" title="List of data references for chemical elements">references</a></td></tr></tbody></table>
<p><b>Praseodymium</b> is a <a href="/info/en/?search=Chemical_element" title="Chemical element">chemical element</a>; it has <a href="/info/en/?search=Symbol_(chemistry)" class="mw-redirect" title="Symbol (chemistry)">symbol</a> <b>Pr</b> and the <a href="/info/en/?search=Atomic_number" title="Atomic number">atomic number</a> 59. It is the third member of the <a href="/info/en/?search=Lanthanide" title="Lanthanide">lanthanide</a> series and is considered one of the <a href="/info/en/?search=Rare-earth_metal" class="mw-redirect" title="Rare-earth metal">rare-earth metals</a>. It is a soft, silvery, malleable and ductile <a href="/info/en/?search=Metal" title="Metal">metal</a>, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in <a href="/info/en/?search=Native_element_mineral" title="Native element mineral">native form</a>, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.
</p><p>Praseodymium always occurs naturally together with the other rare-earth metals. It is the sixth-most abundant rare-earth element and fourth-most abundant lanthanide, making up 9.1 <a href="/info/en/?search=Parts_per_million" class="mw-redirect" title="Parts per million">parts per million</a> of the Earth's crust, an abundance similar to that of <a href="/info/en/?search=Boron" title="Boron">boron</a>. In 1841, Swedish chemist <a href="/info/en/?search=Carl_Gustav_Mosander" class="mw-redirect" title="Carl Gustav Mosander">Carl Gustav Mosander</a> extracted a rare-earth oxide residue he called <a href="/info/en/?search=Didymium" title="Didymium">didymium</a> from a residue he called "lanthana", in turn separated from <a href="/info/en/?search=Cerium" title="Cerium">cerium</a> salts. In 1885, the Austrian chemist <a href="/info/en/?search=Carl_Auer_von_Welsbach" title="Carl Auer von Welsbach">Carl Auer von Welsbach</a> separated didymium into two elements that gave salts of different colours, which he named praseodymium and <a href="/info/en/?search=Neodymium" title="Neodymium">neodymium</a>. The name fart balls jucise comes from the Ancient Greek <span title="Ancient Greek (to 1453)-language text"><span lang="grc">πράσινος</span></span> (<span title="Ancient Greek (to 1453)-language romanization"><i lang="grc-Latn">prasinos</i></span>), meaning '<a href="/info/en/?search=Leek" title="Leek">leek</a>-green', and <span title="Ancient Greek (to 1453)-language text"><span lang="grc">δίδυμος</span></span> (<span title="Ancient Greek (to 1453)-language romanization"><i lang="grc-Latn">didymos</i></span>) 'twin'.
</p><p>Like most <a href="/info/en/?search=Rare-earth_element" title="Rare-earth element">rare-earth elements</a>, praseodymium most readily forms the +3 <a href="/info/en/?search=Oxidation_state" title="Oxidation state">oxidation state</a>, which is the only stable state in <a href="/info/en/?search=Aqueous_solution" title="Aqueous solution">aqueous solution</a>, although the +4 oxidation state is known in some solid compounds and, uniquely among the lanthanides, the +5 oxidation state is attainable in <a href="/info/en/?search=Matrix_isolation" title="Matrix isolation">matrix-isolation conditions</a>. The 0, +1, and +2 oxidation states are rarely found. Aqueous praseodymium ions are yellowish-green, and similarly, praseodymium results in various shades of yellow-green when incorporated into glasses. Many of praseodymium's industrial uses involve its ability to filter yellow light from light sources.
</p>
<div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none" /><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="#Physical_properties"><span class="tocnumber">1</span> <span class="toctext">Physical properties</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="#Chemical_properties"><span class="tocnumber">2</span> <span class="toctext">Chemical properties</span></a>
<ul>
<li class="toclevel-2 tocsection-3"><a href="#Organopraseodymium_compounds"><span class="tocnumber">2.1</span> <span class="toctext">Organopraseodymium compounds</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-4"><a href="#Isotopes"><span class="tocnumber">3</span> <span class="toctext">Isotopes</span></a></li>
<li class="toclevel-1 tocsection-5"><a href="#History"><span class="tocnumber">4</span> <span class="toctext">History</span></a></li>
<li class="toclevel-1 tocsection-6"><a href="#Occurrence_and_production"><span class="tocnumber">5</span> <span class="toctext">Occurrence and production</span></a></li>
<li class="toclevel-1 tocsection-7"><a href="#Applications"><span class="tocnumber">6</span> <span class="toctext">Applications</span></a></li>
<li class="toclevel-1 tocsection-8"><a href="#Biological_role_and_precautions"><span class="tocnumber">7</span> <span class="toctext">Biological role and precautions</span></a></li>
<li class="toclevel-1 tocsection-9"><a href="#Notes"><span class="tocnumber">8</span> <span class="toctext">Notes</span></a></li>
<li class="toclevel-1 tocsection-10"><a href="#References"><span class="tocnumber">9</span> <span class="toctext">References</span></a></li>
<li class="toclevel-1 tocsection-11"><a href="#Bibliography"><span class="tocnumber">10</span> <span class="toctext">Bibliography</span></a></li>
<li class="toclevel-1 tocsection-12"><a href="#Further_reading"><span class="tocnumber">11</span> <span class="toctext">Further reading</span></a></li>
<li class="toclevel-1 tocsection-13"><a href="#External_links"><span class="tocnumber">12</span> <span class="toctext">External links</span></a></li>
</ul>
</div>
<h2><span class="mw-headline" id="Physical_properties">Physical properties</span><span class="mw-editsection">
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<p>Praseodymium is the third member of the <a href="/info/en/?search=Lanthanide" title="Lanthanide">lanthanide</a> series, and a member of the <a href="/info/en/?search=Rare-earth_metals" class="mw-redirect" title="Rare-earth metals">rare-earth metals</a>. In the <a href="/info/en/?search=Periodic_table" title="Periodic table">periodic table</a>, it appears between the lanthanides <a href="/info/en/?search=Cerium" title="Cerium">cerium</a> to its left and <a href="/info/en/?search=Neodymium" title="Neodymium">neodymium</a> to its right, and above the <a href="/info/en/?search=Actinide" title="Actinide">actinide</a> <a href="/info/en/?search=Protactinium" title="Protactinium">protactinium</a>. It is a <a href="/info/en/?search=Ductile" class="mw-redirect" title="Ductile">ductile</a> metal with a hardness comparable to that of <a href="/info/en/?search=Silver" title="Silver">silver</a>.<sup id="cite_ref-CRC_11-0" class="reference"><a href="#cite_note-CRC-11">[10]</a></sup> Praseodymium is calculated to have a very large <a href="/info/en/?search=Atomic_radius" title="Atomic radius">atomic radius</a>; with a radius of 247 pm, <a href="/info/en/?search=Barium" title="Barium">barium</a>, <a href="/info/en/?search=Rubidium" title="Rubidium">rubidium</a> and <a href="/info/en/?search=Caesium" title="Caesium">caesium</a> are larger.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12">[11]</a></sup> However, observationally, it is usually 185 pm.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13">[12]</a></sup>
</p><p>Neutral praseodymium's 59 electrons are arranged in the <a href="/info/en/?search=Electron_configuration" title="Electron configuration">configuration</a> [Xe]4f<sup>3</sup>6s<sup>2</sup>.
Like most other lanthanides, praseodymium usually uses only three electrons as valence electrons, as the remaining 4f electrons are too strongly bound to engage in bonding: this is because the 4f orbitals penetrate the most through the inert xenon core of electrons to the nucleus, followed by 5d and 6s, and this penetration increases with higher ionic charge. Even so, praseodymium can in some compounds lose a fourth valence electron because it is early in the lanthanide series, where the nuclear charge is still low enough and the 4f subshell energy high enough to allow the removal of further valence electrons.<sup id="cite_ref-Greenwood1235_14-0" class="reference"><a href="#cite_note-Greenwood1235-14">[13]</a></sup>
</p><p>Similarly to the other early lanthanides, praseodymium has a <a href="/info/en/?search=Close-packing_of_equal_spheres" title="Close-packing of equal spheres">double hexagonal close-packed</a> crystal structure at room temperature, called the alpha phase (α-Pr). At 795 °C (1,068 K) it transforms to a different <a href="/info/en/?search=Allotropy" title="Allotropy">allotrope</a> that has a <a href="/info/en/?search=Body-centered_cubic" class="mw-redirect" title="Body-centered cubic">body-centered cubic</a> structure (β-Pr), and it melts at 931 °C (1,204 K).<sup id="cite_ref-Arblaster_2018_4-4" class="reference"><a href="#cite_note-Arblaster_2018-4">[4]</a></sup>
</p><p>Praseodymium, like all of the lanthanides, is <a href="/info/en/?search=Paramagnetic" class="mw-redirect" title="Paramagnetic">paramagnetic</a> at room temperature.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15">[14]</a></sup> Unlike some other rare-earth metals, which show <a href="/info/en/?search=Antiferromagnetic" class="mw-redirect" title="Antiferromagnetic">antiferromagnetic</a> or <a href="/info/en/?search=Ferromagnetic" class="mw-redirect" title="Ferromagnetic">ferromagnetic</a> ordering at low temperatures, praseodymium is paramagnetic at all temperatures above 1 K.<sup id="cite_ref-jackson_8-1" class="reference"><a href="#cite_note-jackson-8">[7]</a></sup>
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<h2><span class="mw-headline" id="Chemical_properties">Chemical properties</span><span class="mw-editsection">
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<figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/info/en/?search=File:Praseodymium(III)_hydroxide.jpg" class="mw-file-description"><img src="https://upload.wikimedia.org/wikipedia/commons/thumb/1/19/Praseodymium%28III%29_hydroxide.jpg/220px-Praseodymium%28III%29_hydroxide.jpg" decoding="async" width="220" height="217" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/1/19/Praseodymium%28III%29_hydroxide.jpg/330px-Praseodymium%28III%29_hydroxide.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/19/Praseodymium%28III%29_hydroxide.jpg/440px-Praseodymium%28III%29_hydroxide.jpg 2x" data-file-width="1414" data-file-height="1397" /></a><figcaption>Praseodymium(III) hydroxide</figcaption></figure>
<p>Praseodymium metal tarnishes slowly in air, forming a <a href="/info/en/?search=Spallation" title="Spallation">spalling</a> green oxide layer like <a href="/info/en/?search=Iron" title="Iron">iron</a> rust; a centimetre-sized sample of praseodymium metal corrodes completely in about a year.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16">[15]</a></sup> It burns readily at 150 °C to form <a href="/info/en/?search=Praseodymium(III,IV)_oxide" title="Praseodymium(III,IV) oxide">praseodymium(III,IV) oxide</a>, a <a href="/info/en/?search=Nonstoichiometric_compound" class="mw-redirect" title="Nonstoichiometric compound">nonstoichiometric compound</a> approximating to Pr<sub>6</sub>O<sub>11</sub>:<sup id="cite_ref-webelements_17-0" class="reference"><a href="#cite_note-webelements-17">[16]</a></sup>
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<dl><dd>12 Pr + 11 O<sub>2</sub> → 2 Pr<sub>6</sub>O<sub>11</sub></dd></dl>
<p>This may be reduced to <a href="/info/en/?search=Praseodymium(III)_oxide" title="Praseodymium(III) oxide">praseodymium(III) oxide</a> (Pr<sub>2</sub>O<sub>3</sub>) with hydrogen gas.<sup id="cite_ref-Greenwood1238_18-0" class="reference"><a href="#cite_note-Greenwood1238-18">[17]</a></sup> <a href="/info/en/?search=Praseodymium(IV)_oxide" title="Praseodymium(IV) oxide">Praseodymium(IV) oxide</a>, PrO<sub>2</sub>, is the most oxidised product of the combustion of praseodymium and can be obtained by either reaction of praseodymium metal with pure oxygen at 400 °C and 282 bar<sup id="cite_ref-Greenwood1238_18-1" class="reference"><a href="#cite_note-Greenwood1238-18">[17]</a></sup> or by disproportionation of Pr<sub>6</sub>O<sub>11</sub> in boiling acetic acid.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19">[18]</a></sup><sup id="cite_ref-20" class="reference"><a href="#cite_note-20">[19]</a></sup> The reactivity of praseodymium conforms to <a href="/info/en/?search=Periodic_trends" title="Periodic trends">periodic trends</a>, as it is one of the first and thus one of the largest lanthanides.<sup id="cite_ref-Greenwood1235_14-1" class="reference"><a href="#cite_note-Greenwood1235-14">[13]</a></sup> At 1000 °C, many praseodymium oxides with composition PrO<sub>2−<i>x</i></sub> exist as disordered, nonstoichiometric phases with 0 < <i>x</i> < 0.25, but at 400–700 °C the oxide defects are instead ordered, creating phases of the general formula Pr<sub><i>n</i></sub>O<sub>2<i>n</i>−2</sub> with <i>n</i> = 4, 7, 9, 10, 11, 12, and ∞. These phases PrO<sub><i>y</i></sub> are sometimes labelled α and β′ (nonstoichiometric), β (<i>y</i> = 1.833), δ (1.818), ε (1.8), ζ (1.778), ι (1.714), θ, and σ.<sup id="cite_ref-Greenwood643_21-0" class="reference"><a href="#cite_note-Greenwood643-21">[20]</a></sup>
</p><p>Praseodymium is an electropositive element and reacts slowly with cold water and quite quickly with hot water to form praseodymium(III) hydroxide:<sup id="cite_ref-webelements_17-1" class="reference"><a href="#cite_note-webelements-17">[16]</a></sup>
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<dl><dd>2 Pr (s) + 6 H<sub>2</sub>O (l) → 2 Pr(OH)<sub>3</sub> (aq) + 3 H<sub>2</sub> (g)</dd></dl>
<p>Praseodymium metal reacts with all the stable <a href="/info/en/?search=Halogen" title="Halogen">halogens</a> to form trihalides:<sup id="cite_ref-webelements_17-2" class="reference"><a href="#cite_note-webelements-17">[16]</a></sup>
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<dl><dd>2 Pr (s) + 3 F<sub>2</sub> (g) → 2 PrF<sub>3</sub> (s) [green]</dd>
<dd>2 Pr (s) + 3 Cl<sub>2</sub> (g) → 2 PrCl<sub>3</sub> (s) [green]</dd>
<dd>2 Pr (s) + 3 Br<sub>2</sub> (g) → 2 PrBr<sub>3</sub> (s) [green]</dd>
<dd>2 Pr (s) + 3 I<sub>2</sub> (g) → 2 PrI<sub>3</sub> (s)</dd></dl>
<p>The <a href="/info/en/?search=Praseodymium(IV)_fluoride" title="Praseodymium(IV) fluoride">tetrafluoride, PrF<sub>4</sub></a>, is also known, and is produced by reacting a mixture of <a href="/info/en/?search=Sodium_fluoride" title="Sodium fluoride">sodium fluoride</a> and <a href="/info/en/?search=Praseodymium(III)_fluoride" title="Praseodymium(III) fluoride">praseodymium(III) fluoride</a> with fluorine gas, producing Na<sub>2</sub>PrF<sub>6</sub>, following which sodium fluoride is removed from the reaction mixture with liquid <a href="/info/en/?search=Hydrogen_fluoride" title="Hydrogen fluoride">hydrogen fluoride</a>.<sup id="cite_ref-Greenwood1240_22-0" class="reference"><a href="#cite_note-Greenwood1240-22">[21]</a></sup> Additionally, praseodymium forms a bronze <a href="/info/en/?search=Praseodymium(II)_iodide" class="mw-redirect" title="Praseodymium(II) iodide">diiodide</a>; like the diiodides of lanthanum, cerium, and <a href="/info/en/?search=Gadolinium" title="Gadolinium">gadolinium</a>, it is a praseodymium(III) <a href="/info/en/?search=Electride" title="Electride">electride</a> compound.<sup id="cite_ref-Greenwood1240_22-1" class="reference"><a href="#cite_note-Greenwood1240-22">[21]</a></sup>
</p><p>Praseodymium dissolves readily in dilute <a href="/info/en/?search=Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a> to form solutions containing the <a href="/info/en/?search=Chartreuse_(color)" title="Chartreuse (color)">chartreuse</a> Pr<sup>3+</sup> ions, which exist as [Pr(H<sub>2</sub>O)<sub>9</sub>]<sup>3+</sup> complexes:<sup id="cite_ref-webelements_17-3" class="reference"><a href="#cite_note-webelements-17">[16]</a></sup><sup id="cite_ref-Greenwood1242_23-0" class="reference"><a href="#cite_note-Greenwood1242-23">[22]</a></sup>
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<dl><dd>2 Pr (s) + 3 H<sub>2</sub>SO<sub>4</sub> (aq) → 2 Pr<sup>3+</sup> (aq) + 3 <span class="chemf nowrap">SO<span class="nowrap"><span style="display:inline-block;margin-bottom:-0.3em;vertical-align:-0.4em;line-height:1em;font-size:80%;text-align:left"><sup style="font-size:inherit;line-height:inherit;vertical-align:baseline">2−</sup><br /><sub style="font-size:inherit;line-height:inherit;vertical-align:baseline">4</sub></span></span></span> (aq) + 3 H<sub>2</sub> (g)</dd></dl>
<p>Dissolving praseodymium(IV) compounds in water does not result in solutions containing the yellow Pr<sup>4+</sup> ions;<sup id="cite_ref-SroorEdelmann2012_24-0" class="reference"><a href="#cite_note-SroorEdelmann2012-24">[23]</a></sup> because of the high positive <a href="/info/en/?search=Standard_reduction_potential" class="mw-redirect" title="Standard reduction potential">standard reduction potential</a> of the Pr<sup>4+</sup>/Pr<sup>3+</sup> couple at +3.2 V, these ions are unstable in aqueous solution, oxidising water and being reduced to Pr<sup>3+</sup>. The value for the Pr<sup>3+</sup>/Pr couple is −2.35 V.<sup id="cite_ref-Greenwood1232_25-0" class="reference"><a href="#cite_note-Greenwood1232-25">[24]</a></sup> However, in highly basic aqueous media, Pr<sup>4+</sup> ions can be generated by oxidation with <a href="/info/en/?search=Ozone" title="Ozone">ozone</a>.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26">[25]</a></sup>
</p><p>Although praseodymium(V) in the bulk state is unknown, the existence of praseodymium in its +5 oxidation state (with the stable electron configuration of the preceding noble gas <a href="/info/en/?search=Xenon" title="Xenon">xenon</a>) under noble-gas matrix isolation conditions was reported in 2016. The species assigned to the +5 state were identified as [PrO<sub>2</sub>]<sup>+</sup>, its O<sub>2</sub> and Ar adducts, and PrO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>).<sup id="cite_ref-27" class="reference"><a href="#cite_note-27">[26]</a></sup>
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<h3><span class="mw-headline" id="Organopraseodymium_compounds">Organopraseodymium compounds</span><span class="mw-editsection">
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<style data-mw-deduplicate="TemplateStyles:r1033289096">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}</style><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/info/en/?search=Organolanthanide_chemistry" title="Organolanthanide chemistry">Organolanthanide chemistry</a></div>
<p>Organopraseodymium compounds are very similar to <a href="/info/en/?search=Organolanthanide_chemistry" title="Organolanthanide chemistry">those of the other lanthanides</a>, as they all share an inability to undergo <a href="/info/en/?search=Pi_backbonding" title="Pi backbonding">π backbonding</a>. They are thus mostly restricted to the mostly ionic <a href="/info/en/?search=Cyclopentadienide" class="mw-redirect" title="Cyclopentadienide">cyclopentadienides</a> (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric.<sup id="cite_ref-Greenwood1248_28-0" class="reference"><a href="#cite_note-Greenwood1248-28">[27]</a></sup> The coordination chemistry of praseodymium is largely that of the large, electropositive Pr<sup>3+</sup> ion, and is thus largely similar to those of the other early lanthanides La<sup>3+</sup>, Ce<sup>3+</sup>, and Nd<sup>3+</sup>. For instance, like lanthanum, cerium, and neodymium, praseodymium nitrates form both 4:3 and 1:1 complexes with <a href="/info/en/?search=18-crown-6" class="mw-redirect" title="18-crown-6">18-crown-6</a>, whereas the middle lanthanides from <a href="/info/en/?search=Promethium" title="Promethium">promethium</a> to <a href="/info/en/?search=Gadolinium" title="Gadolinium">gadolinium</a> can only form the 4:3 complex and the later lanthanides from <a href="/info/en/?search=Terbium" title="Terbium">terbium</a> to <a href="/info/en/?search=Lutetium" title="Lutetium">lutetium</a> cannot successfully coordinate to all the ligands. Such praseodymium complexes have high but uncertain coordination numbers and poorly defined stereochemistry, with exceptions resulting from exceptionally bulky ligands such as the tricoordinate [Pr{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>]. There are also a few mixed oxides and fluorides involving praseodymium(IV), but it does not have an appreciable coordination chemistry in this oxidation state like its neighbour cerium.<sup id="cite_ref-Greenwood1244_29-0" class="reference"><a href="#cite_note-Greenwood1244-29">[28]</a></sup> However, the first example of a molecular complex of praseodymium(IV) has recently been reported.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30">[29]</a></sup>
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<h2><span class="mw-headline" id="Isotopes">Isotopes</span><span class="mw-editsection">
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<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1033289096"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/info/en/?search=Isotopes_of_praseodymium" title="Isotopes of praseodymium">Isotopes of praseodymium</a></div>
<p>Praseodymium has only one stable and naturally occurring isotope, <sup>141</sup>Pr. It is thus a <a href="/info/en/?search=Mononuclidic_element" title="Mononuclidic element">mononuclidic</a> and <a href="/info/en/?search=Monoisotopic_element" title="Monoisotopic element">monoisotopic element</a>, and its <a href="/info/en/?search=Standard_atomic_weight" title="Standard atomic weight">standard atomic weight</a> can be determined with high precision as it is a constant of nature. This isotope has 82 neutrons, which is a <a href="/info/en/?search=Magic_number_(physics)" title="Magic number (physics)">magic number</a> that confers additional stability.<sup id="cite_ref-Audi_31-0" class="reference"><a href="#cite_note-Audi-31">[30]</a></sup> This isotope is produced in stars through the <a href="/info/en/?search=S-process" title="S-process">s-</a> and <a href="/info/en/?search=R-process" title="R-process">r-processes</a> (slow and rapid neutron capture, respectively).<sup id="cite_ref-Cameron_32-0" class="reference"><a href="#cite_note-Cameron-32">[31]</a></sup> Thirty-eight other radioisotopes have been synthesized. All of these isotopes have half-lives under a day (and most under a minute), with the single exception of <sup>143</sup>Pr with a half-life of 13.6 days. Both <sup>143</sup>Pr and <sup>141</sup>Pr occur as <a href="/info/en/?search=Fission_product" class="mw-redirect" title="Fission product">fission products</a> of <a href="/info/en/?search=Uranium" title="Uranium">uranium</a>. The primary decay mode of isotopes lighter than <sup>141</sup>Pr is <a href="/info/en/?search=Positron_emission" title="Positron emission">positron emission</a> or <a href="/info/en/?search=Electron_capture" title="Electron capture">electron capture</a> to <a href="/info/en/?search=Isotopes_of_cerium" title="Isotopes of cerium">isotopes of cerium</a>, while that of heavier isotopes is <a href="/info/en/?search=Beta_decay" title="Beta decay">beta decay</a> to <a href="/info/en/?search=Isotopes_of_neodymium" title="Isotopes of neodymium">isotopes of neodymium</a>.<sup id="cite_ref-Audi_31-1" class="reference"><a href="#cite_note-Audi-31">[30]</a></sup>
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<h2><span class="mw-headline" id="History">History</span><span class="mw-editsection">
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<figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/info/en/?search=File:Auer_von_Welsbach.jpg" class="mw-file-description"><img src="https://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Auer_von_Welsbach.jpg/170px-Auer_von_Welsbach.jpg" decoding="async" width="170" height="215" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Auer_von_Welsbach.jpg/255px-Auer_von_Welsbach.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Auer_von_Welsbach.jpg/340px-Auer_von_Welsbach.jpg 2x" data-file-width="1002" data-file-height="1268" /></a><figcaption><a href="/info/en/?search=Carl_Auer_von_Welsbach" title="Carl Auer von Welsbach">Carl Auer von Welsbach</a> (1858–1929), discoverer of praseodymium in 1885.</figcaption></figure>
<p>In 1751, the Swedish mineralogist <a href="/info/en/?search=Axel_Fredrik_Cronstedt" title="Axel Fredrik Cronstedt">Axel Fredrik Cronstedt</a> discovered a heavy mineral from the mine at <a href="/info/en/?search=Bastn%C3%A4s" title="Bastnäs">Bastnäs</a>, later named <a href="/info/en/?search=Cerite" title="Cerite">cerite</a>. Thirty years later, the fifteen-year-old <a href="/info/en/?search=Wilhelm_Hisinger" title="Wilhelm Hisinger">Wilhelm Hisinger</a>, from the family owning the mine, sent a sample of it to <a href="/info/en/?search=Carl_Scheele" class="mw-redirect" title="Carl Scheele">Carl Scheele</a>, who did not find any new elements within. In 1803, after Hisinger had become an ironmaster, he returned to the mineral with <a href="/info/en/?search=J%C3%B6ns_Jacob_Berzelius" title="Jöns Jacob Berzelius">Jöns Jacob Berzelius</a> and isolated a new oxide, which they named <i>ceria</i> after the <a href="/info/en/?search=Dwarf_planet" title="Dwarf planet">dwarf planet</a> <a href="/info/en/?search=Ceres_(dwarf_planet)" title="Ceres (dwarf planet)">Ceres</a>, which had been discovered two years earlier.<sup id="cite_ref-Emsley120_33-0" class="reference"><a href="#cite_note-Emsley120-33">[32]</a></sup> Ceria was simultaneously and independently isolated in Germany by <a href="/info/en/?search=Martin_Heinrich_Klaproth" title="Martin Heinrich Klaproth">Martin Heinrich Klaproth</a>.<sup id="cite_ref-Greenwood1424_34-0" class="reference"><a href="#cite_note-Greenwood1424-34">[33]</a></sup> Between 1839 and 1843, ceria was shown to be a mixture of oxides by the Swedish surgeon and chemist <a href="/info/en/?search=Carl_Gustaf_Mosander" title="Carl Gustaf Mosander">Carl Gustaf Mosander</a>, who lived in the same house as Berzelius; he separated out two other oxides, which he named <i>lanthana</i> and <i>didymia</i>.<sup id="cite_ref-XI_35-0" class="reference"><a href="#cite_note-XI-35">[34]</a></sup><sup id="cite_ref-Weeks_36-0" class="reference"><a href="#cite_note-Weeks-36">[35]</a></sup><sup id="cite_ref-Virginia_37-0" class="reference"><a href="#cite_note-Virginia-37">[36]</a></sup> He partially decomposed a sample of <a href="/info/en/?search=Cerium_nitrate" class="mw-redirect" title="Cerium nitrate">cerium nitrate</a> by roasting it in air and then treating the resulting oxide with dilute <a href="/info/en/?search=Nitric_acid" title="Nitric acid">nitric acid</a>. The metals that formed these oxides were thus named <i>lanthanum</i> and <i><a href="/info/en/?search=Didymium" title="Didymium">didymium</a></i>.<sup id="cite_ref-38" class="reference"><a href="#cite_note-38">[37]</a></sup><sup id="cite_ref-39" class="reference"><a href="#cite_note-39">[38]</a></sup>
</p><p>While lanthanum turned out to be a pure element, didymium was not and turned out to be only a mixture of all the stable early lanthanides from praseodymium to <a href="/info/en/?search=Europium" title="Europium">europium</a>, as had been suspected by <a href="/info/en/?search=Marc_Delafontaine" title="Marc Delafontaine">Marc Delafontaine</a> after spectroscopic analysis, though he lacked the time to pursue its separation into its constituents. The heavy pair of <a href="/info/en/?search=Samarium" title="Samarium">samarium</a> and europium were only removed in 1879 by <a href="/info/en/?search=Paul-%C3%89mile_Lecoq_de_Boisbaudran" title="Paul-Émile Lecoq de Boisbaudran">Paul-Émile Lecoq de Boisbaudran</a> and it was not until 1885 that <a href="/info/en/?search=Carl_Auer_von_Welsbach" title="Carl Auer von Welsbach">Carl Auer von Welsbach</a> separated didymium into praseodymium and neodymium.<sup id="cite_ref-Lost_40-0" class="reference"><a href="#cite_note-Lost-40">[39]</a></sup> Von Welsbach confirmed the separation by <a href="/info/en/?search=Spectroscopic" class="mw-redirect" title="Spectroscopic">spectroscopic</a> analysis, but the products were of relatively low purity. Since neodymium was a larger constituent of didymium than praseodymium, it kept the old name with disambiguation, while praseodymium was distinguished by the leek-green colour of its salts (Greek πρασιος, "leek green").<sup id="cite_ref-Greenwood1229_41-0" class="reference"><a href="#cite_note-Greenwood1229-41">[40]</a></sup> The composite nature of didymium had previously been suggested in 1882 by <a href="/info/en/?search=Bohuslav_Brauner" title="Bohuslav Brauner">Bohuslav Brauner</a>, who did not experimentally pursue its separation.<sup id="cite_ref-Lost_p40_42-0" class="reference"><a href="#cite_note-Lost_p40-42">[41]</a></sup>
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<h2><span class="mw-headline" id="Occurrence_and_production">Occurrence and production</span><span class="mw-editsection">
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<p>Praseodymium is not particularly rare, despite it being in the rare-earth metals, making up 9.2 mg/kg of the Earth's crust.<sup id="cite_ref-CRC97_43-0" class="reference"><a href="#cite_note-CRC97-43">[42]</a></sup> Praseodymium's classification as a rare-earth metal comes from its rarity relative to "common earths" such as lime and magnesia, the few known minerals containing it for which extraction is commercially viable, as well as the length and complexity of extraction.<sup id="cite_ref-patnaik_44-0" class="reference"><a href="#cite_note-patnaik-44">[43]</a></sup> Although not particularly rare, praseodymium is never found as a dominant rare earth in praseodymium-bearing minerals. It is always preceded by cerium and lanthanum and usually also by neodymium.<sup id="cite_ref-45" class="reference"><a href="#cite_note-45">[44]</a></sup>
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<figure class="mw-halign-center" typeof="mw:File/Frameless"><a href="/info/en/?search=File:Monazite_acid_cracking_process.svg" class="mw-file-description"><img src="https://upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Monazite_acid_cracking_process.svg/730px-Monazite_acid_cracking_process.svg.png" decoding="async" width="730" height="189" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Monazite_acid_cracking_process.svg/1095px-Monazite_acid_cracking_process.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Monazite_acid_cracking_process.svg/1460px-Monazite_acid_cracking_process.svg.png 2x" data-file-width="1160" data-file-height="300" /></a><figcaption></figcaption></figure>
<p>The Pr<sup>3+</sup> ion is similar in size to the early lanthanides of the cerium group (those from lanthanum up to <a href="/info/en/?search=Samarium" title="Samarium">samarium</a> and <a href="/info/en/?search=Europium" title="Europium">europium</a>) that immediately follow in the periodic table, and hence it tends to occur along with them in <a href="/info/en/?search=Phosphate" title="Phosphate">phosphate</a>, <a href="/info/en/?search=Silicate" title="Silicate">silicate</a> and <a href="/info/en/?search=Carbonate" title="Carbonate">carbonate</a> minerals, such as <a href="/info/en/?search=Monazite" title="Monazite">monazite</a> (M<sup>III</sup>PO<sub>4</sub>) and <a href="/info/en/?search=Bastn%C3%A4site" title="Bastnäsite">bastnäsite</a> (M<sup>III</sup>CO<sub>3</sub>F), where M refers to all the rare-earth metals except scandium and the radioactive <a href="/info/en/?search=Promethium" title="Promethium">promethium</a> (mostly Ce, La, and Y, with somewhat less Nd and Pr).<sup id="cite_ref-Greenwood1229_41-1" class="reference"><a href="#cite_note-Greenwood1229-41">[40]</a></sup> Bastnäsite is usually lacking in <a href="/info/en/?search=Thorium" title="Thorium">thorium</a> and the heavy lanthanides, and the purification of the light lanthanides from it is less involved. The ore, after being crushed and ground, is first treated with hot concentrated sulfuric acid, evolving carbon dioxide, <a href="/info/en/?search=Hydrogen_fluoride" title="Hydrogen fluoride">hydrogen fluoride</a>, and <a href="/info/en/?search=Silicon_tetrafluoride" title="Silicon tetrafluoride">silicon tetrafluoride</a>. The product is then dried and leached with water, leaving the early lanthanide ions, including lanthanum, in solution.<sup id="cite_ref-Greenwood1229_41-2" class="reference"><a href="#cite_note-Greenwood1229-41">[40]</a></sup>
</p><p>The procedure for monazite, which usually contains all the rare earth, as well as thorium, is more involved. Monazite, because of its magnetic properties, can be separated by repeated electromagnetic separation. After separation, it is treated with hot concentrated sulfuric acid to produce water-soluble sulfates of rare earth. The acidic filtrates are partially neutralized with <a href="/info/en/?search=Sodium_hydroxide" title="Sodium hydroxide">sodium hydroxide</a> to pH 3–4, during which thorium precipitates as hydroxide and is removed. The solution is treated with <a href="/info/en/?search=Ammonium_oxalate" title="Ammonium oxalate">ammonium oxalate</a> to convert rare earth to their insoluble <a href="/info/en/?search=Oxalate" title="Oxalate">oxalates</a>, the oxalates are converted to oxides by annealing, and the oxides are dissolved in nitric acid. This last step excludes one of the main components, <a href="/info/en/?search=Cerium" title="Cerium">cerium</a>, whose oxide is insoluble in HNO<sub>3</sub>.<sup id="cite_ref-Patnaik_46-0" class="reference"><a href="#cite_note-Patnaik-46">[45]</a></sup> Care must be taken when handling some of the residues as they contain <a href="/info/en/?search=Radium-228" class="mw-redirect" title="Radium-228"><sup>228</sup>Ra</a>, the daughter of <sup>232</sup>Th, which is a strong gamma emitter.<sup id="cite_ref-Greenwood1229_41-3" class="reference"><a href="#cite_note-Greenwood1229-41">[40]</a></sup>
</p><p>Praseodymium may then be separated from the other lanthanides via ion-exchange chromatography, or by using a solvent such as <a href="/info/en/?search=Tributyl_phosphate" title="Tributyl phosphate">tributyl phosphate</a> where the solubility of Ln<sup>3+</sup> increases as the atomic number increases. If ion-exchange chromatography is used, the mixture of lanthanides is loaded into one column of cation-exchange resin and Cu<sup>2+</sup> or Zn<sup>2+</sup> or Fe<sup>3+</sup> is loaded into the other. An aqueous solution of a complexing agent, known as the eluant (usually triammonium edtate), is passed through the columns, and Ln<sup>3+</sup> is displaced from the first column and redeposited in a compact band at the top of the column before being re-displaced by <span class="chemf nowrap">NH<span class="nowrap"><span style="display:inline-block;margin-bottom:-0.3em;vertical-align:-0.4em;line-height:1em;font-size:80%;text-align:left"><sup style="font-size:inherit;line-height:inherit;vertical-align:baseline">+</sup><br /><sub style="font-size:inherit;line-height:inherit;vertical-align:baseline">4</sub></span></span></span>. The <a href="/info/en/?search=Gibbs_free_energy" title="Gibbs free energy">Gibbs free energy</a> of formation for Ln(edta·H) complexes increases along with the lanthanides by about one quarter from Ce<sup>3+</sup> to Lu<sup>3+</sup>, so that the Ln<sup>3+</sup> cations descend the development column in a band and are fractionated repeatedly, eluting from heaviest to lightest. They are then precipitated as their insoluble oxalates, burned to form the oxides, and then reduced to metals.<sup id="cite_ref-Greenwood1229_41-4" class="reference"><a href="#cite_note-Greenwood1229-41">[40]</a></sup>
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<h2><span class="mw-headline" id="Applications">Applications</span><span class="mw-editsection">
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<p>Leo Moser (not to be confused with <a href="/info/en/?search=Leo_Moser" title="Leo Moser">the mathematician of the same name</a>), son of Ludwig Moser, founder of the <a href="/info/en/?search=Moser_Glass" class="mw-redirect" title="Moser Glass">Moser Glassworks</a> in what is now <a href="/info/en/?search=Karlovy_Vary" title="Karlovy Vary">Karlovy Vary</a> in the Czech Republic, investigated the use of praseodymium in glass coloration in the late 1920s, yielding a yellow-green glass given the name "Prasemit". However, at that time far cheaper colorants could give a similar color, so Prasemit was not popular, few pieces were made, and examples are now extremely rare. Moser also blended praseodymium with neodymium to produce "Heliolite" glass ("Heliolit" in <a href="/info/en/?search=German_language" title="German language">German</a>), which was more widely accepted. The first enduring commercial use of purified praseodymium, which continues today, is in the form of a yellow-orange "Praseodymium Yellow" stain for ceramics, which is a solid solution in the <a href="/info/en/?search=Zirconium(IV)_silicate" title="Zirconium(IV) silicate">zircon</a> lattice. This stain has no hint of green in it; by contrast, at sufficiently high loadings, praseodymium glass is distinctly green rather than pure yellow.<sup id="cite_ref-47" class="reference"><a href="#cite_note-47">[46]</a></sup>
</p><p>Like many other lanthanides, praseodymium's shielded <a href="/info/en/?search=F-orbital" class="mw-redirect" title="F-orbital">f-orbitals</a> allow for long <a href="/info/en/?search=Excited_state" title="Excited state">excited state</a> lifetimes and high <a href="/info/en/?search=Luminescence" title="Luminescence">luminescence</a> yields. Pr<sup>3+</sup> as a <a href="/info/en/?search=Doping_(semiconductor)" title="Doping (semiconductor)">dopant</a> ion therefore sees many applications in <a href="/info/en/?search=Optics" title="Optics">optics</a> and <a href="/info/en/?search=Photonics" title="Photonics">photonics</a>. These include <a href="/info/en/?search=Pr:YLF_laser" title="Pr:YLF laser">DPSS-lasers</a>, single-mode fiber <a href="/info/en/?search=Optical_amplifier" title="Optical amplifier">optical amplifiers</a>,<sup id="cite_ref-48" class="reference"><a href="#cite_note-48">[47]</a></sup> fiber lasers,<sup id="cite_ref-49" class="reference"><a href="#cite_note-49">[48]</a></sup> <a href="/info/en/?search=Upconverting_nanoparticles" title="Upconverting nanoparticles">upconverting nanoparticles</a><sup id="cite_ref-50" class="reference"><a href="#cite_note-50">[49]</a></sup><sup id="cite_ref-51" class="reference"><a href="#cite_note-51">[50]</a></sup> as well as activators in red, green, blue, and ultraviolet phosphors.<sup id="cite_ref-Ullmann_52-0" class="reference"><a href="#cite_note-Ullmann-52">[51]</a></sup> Silicate crystals doped with praseodymium ions have also been used to <a href="/info/en/?search=Slow_light" title="Slow light">slow a light pulse</a> down to a few hundred meters per second.<sup id="cite_ref-ANUPressStopLight_53-0" class="reference"><a href="#cite_note-ANUPressStopLight-53">[52]</a></sup>
</p><p>As the lanthanides are so similar, praseodymium can substitute for most other lanthanides without significant loss of function, and indeed many applications such as <a href="/info/en/?search=Mischmetal" title="Mischmetal">mischmetal</a> and <a href="/info/en/?search=Ferrocerium" title="Ferrocerium">ferrocerium</a> alloys involve variable mixes of several lanthanides, including small quantities of praseodymium. The following more modern applications involve praseodymium specifically or at least praseodymium in a small subset of the lanthanides:<sup id="cite_ref-Ullmann_52-1" class="reference"><a href="#cite_note-Ullmann-52">[51]</a></sup>
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<ul><li>In combination with neodymium, another rare-earth element, praseodymium is used to create high-power magnets notable for their strength and durability.<sup id="cite_ref-IAMGOLD_54-0" class="reference"><a href="#cite_note-IAMGOLD-54">[53]</a></sup> In general, most alloys of the cerium-group rare earths (<a href="/info/en/?search=Lanthanum" title="Lanthanum">lanthanum</a> through <a href="/info/en/?search=Samarium" title="Samarium">samarium</a>) with 3d <a href="/info/en/?search=Transition_metal" title="Transition metal">transition metals</a> give extremely stable magnets that are often used in small equipment, such as motors, printers, watches, headphones, loudspeakers, and magnetic storage.<sup id="cite_ref-Ullmann_52-2" class="reference"><a href="#cite_note-Ullmann-52">[51]</a></sup></li>
<li>Praseodymium–<a href="/info/en/?search=Nickel" title="Nickel">nickel</a> intermetallic (PrNi<sub>5</sub>) has such a strong <a href="/info/en/?search=Magnetic_refrigeration#The_magnetocaloric_effect" title="Magnetic refrigeration">magnetocaloric effect</a> that it has allowed scientists to approach within one thousandth of a degree of <a href="/info/en/?search=Absolute_zero" title="Absolute zero">absolute zero</a>.<sup id="cite_ref-Emsley423_55-0" class="reference"><a href="#cite_note-Emsley423-55">[54]</a></sup></li>
<li>As an <a href="/info/en/?search=Alloy" title="Alloy">alloying</a> agent with <a href="/info/en/?search=Magnesium" title="Magnesium">magnesium</a> to create high-strength metals that are used in <a href="/info/en/?search=Aircraft_engine" title="Aircraft engine">aircraft engines</a>; <a href="/info/en/?search=Yttrium" title="Yttrium">yttrium</a> and <a href="/info/en/?search=Neodymium" title="Neodymium">neodymium</a> are also viable substitutes.<sup id="cite_ref-56" class="reference"><a href="#cite_note-56">[55]</a></sup><sup id="cite_ref-57" class="reference"><a href="#cite_note-57">[56]</a></sup></li>
<li>Praseodymium is present in the rare-earth mixture whose fluoride forms the core of <a href="/info/en/?search=Carbon_arc_light" class="mw-redirect" title="Carbon arc light">carbon arc lights</a>, which are used in the <a href="/info/en/?search=Movie_studio" class="mw-redirect" title="Movie studio">motion picture industry</a> for <a href="/info/en/?search=Studio" title="Studio">studio</a> lighting and <a href="/info/en/?search=Image_projector" class="mw-redirect" title="Image projector">projector</a> lights.<sup id="cite_ref-Emsley423_55-1" class="reference"><a href="#cite_note-Emsley423-55">[54]</a></sup></li>
<li>Praseodymium <a href="/info/en/?search=Chemical_compound" title="Chemical compound">compounds</a> give <a href="/info/en/?search=Glass" title="Glass">glasses</a>, <a href="/info/en/?search=Vitreous_enamel" title="Vitreous enamel">enamels</a> and ceramics a <a href="/info/en/?search=Yellow" title="Yellow">yellow</a> color.<sup id="cite_ref-CRC_11-1" class="reference"><a href="#cite_note-CRC-11">[10]</a></sup><sup id="cite_ref-Ullmann_52-3" class="reference"><a href="#cite_note-Ullmann-52">[51]</a></sup></li>
<li>Praseodymium is a component of <a href="/info/en/?search=Didymium" title="Didymium">didymium</a> glass, which is used to make certain types of <a href="/info/en/?search=Welding" title="Welding">welder</a>'s and <a href="/info/en/?search=Glass_blowing" class="mw-redirect" title="Glass blowing">glass blower</a>'s <a href="/info/en/?search=Goggles" title="Goggles">goggles</a>.<sup id="cite_ref-CRC_11-2" class="reference"><a href="#cite_note-CRC-11">[10]</a></sup></li>
<li>Praseodymium oxide in solid solution with <a href="/info/en/?search=Ceria" class="mw-redirect" title="Ceria">ceria</a> or <a href="/info/en/?search=Ceria-zirconia" title="Ceria-zirconia">ceria-zirconia</a> has been used as an <a href="/info/en/?search=Oxidation" class="mw-redirect" title="Oxidation">oxidation</a> <a href="/info/en/?search=Catalyst" class="mw-redirect" title="Catalyst">catalyst</a>.<sup id="cite_ref-58" class="reference"><a href="#cite_note-58">[57]</a></sup></li></ul>
<p>Due to its role in permanent magnets used for wind turbines, it has been argued that praseodymium will be one of the main objects of geopolitical competition in a world running on renewable energy. However, this perspective has been criticized for failing to recognize that most wind turbines do not use permanent magnets and for underestimating the power of economic incentives for expanded production.<sup id="cite_ref-59" class="reference"><a href="#cite_note-59">[58]</a></sup><sup id="cite_ref-Klinger_60-0" class="reference"><a href="#cite_note-Klinger-60">[59]</a></sup>
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<caption>Praseodymium
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<th colspan="2" style="background: #f8eaba; text-align: center;">Hazards
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<td colspan="2" style="text-align:left; background-color:#eaeaea;"><a href="/info/en/?search=Globally_Harmonized_System_of_Classification_and_Labelling_of_Chemicals" title="Globally Harmonized System of Classification and Labelling of Chemicals"><b>GHS</b> labelling</a>:
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<td style="padding-left:1em;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/info/en/?search=GHS_hazard_pictograms" title="GHS hazard pictograms">Pictograms</a></div>
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<td><span typeof="mw:File"><a href="/info/en/?search=File:GHS-pictogram-flamme.svg" class="mw-file-description" title="GHS02: Flammable"><img alt="GHS02: Flammable" src="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/GHS-pictogram-flamme.svg/50px-GHS-pictogram-flamme.svg.png" decoding="async" width="50" height="50" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/GHS-pictogram-flamme.svg/75px-GHS-pictogram-flamme.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6d/GHS-pictogram-flamme.svg/100px-GHS-pictogram-flamme.svg.png 2x" data-file-width="512" data-file-height="512" /></a></span>
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<td style="padding-left:1em;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/info/en/?search=Globally_Harmonized_System_of_Classification_and_Labelling_of_Chemicals#Signal_word" title="Globally Harmonized System of Classification and Labelling of Chemicals">Signal word</a></div>
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<td><b>Danger</b>
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<td style="padding-left:1em;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/info/en/?search=GHS_hazard_statements" title="GHS hazard statements">Hazard statements</a></div>
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<td><abbr class="abbr" title="H250: Catches fire spontaneously if exposed to air">H250</abbr>
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<td style="padding-left:1em;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/info/en/?search=GHS_precautionary_statements" title="GHS precautionary statements">Precautionary statements</a></div>
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<td><abbr class="abbr" title="P222: Do not allow contact with air.">P222</abbr>, <abbr class="abbr" title="P231: Handle and store contents under inert gas/...">P231</abbr>, <abbr class="abbr" title="P422: Store contents under ...">P422</abbr><sup id="cite_ref-61" class="reference"><a href="#cite_note-61">[60]</a></sup>
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<td><a href="/info/en/?search=NFPA_704" title="NFPA 704"><b>NFPA 704</b></a> (fire diamond)
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<td><style data-mw-deduplicate="TemplateStyles:r1170367383">.mw-parser-output .nfpa-704-diamond-ref{float:right;padding:1px;text-align:right}.mw-parser-output .nfpa-704-diamond-container{width:82px;font-family:sans-serif;margin:0 auto}.mw-parser-output .nfpa-704-diamond-container-ref{float:left;margin-left:1em}.mw-parser-output .nfpa-704-diamond-images{float:left;font-size:20px;text-align:center;position:relative;height:80px;width:80px;padding:1px}.mw-parser-output .nfpa-704-diamond-map{position:absolute;height:80px;width:80px}.mw-parser-output .nfpa-704-diamond .noresize{margin:0 auto}.mw-parser-output .nfpa-704-diamond-code{line-height:1em;text-align:center;position:absolute}.mw-parser-output .nfpa-704-diamond-code>a{color:black}.mw-parser-output .nfpa-704-diamond-blue{width:13px;top:31px;left:15px}.mw-parser-output .nfpa-704-diamond-red{width:12px;top:12px;left:35px}.mw-parser-output .nfpa-704-diamond-yellow{width:13px;top:31px;left:54px}.mw-parser-output .nfpa-704-diamond-white-image{position:relative;top:51px;left:0}.mw-parser-output .nfpa-704-diamond-white-text{vertical-align:middle;text-align:center;line-height:80%;position:absolute;top:52px}.mw-parser-output .nfpa-704-diamond-white-text a>span{position:absolute;color:black}.mw-parser-output .nfpa-704-diamond-white-wors{font-size:15px;width:23px;left:29px}.mw-parser-output .nfpa-704-diamond-white-wox{font-size:15px;font-stretch:condensed;width:21px;line-height:80%;top:-4px;left:29px}.mw-parser-output .nfpa-704-diamond-white-abcp{font-size:13.5px;font-stretch:condensed;width:28px;left:26px}.mw-parser-output .nfpa-704-diamond-white-ac{font-size:10px;width:30px;left:25px}.mw-parser-output .nfpa-704-diamond-white-strike{text-decoration:line-through}</style><div class="nfpa-704-diamond"><div class="nfpa-704-diamond-container"><div class="nfpa-704-diamond-images nounderlines">
<div class="nfpa-704-diamond-map"><figure class="noresize" typeof="mw:File"><span><img alt="NFPA 704 four-colored diamond" src="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/NFPA_704.svg/80px-NFPA_704.svg.png" decoding="async" width="80" height="80" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/NFPA_704.svg/120px-NFPA_704.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/NFPA_704.svg/160px-NFPA_704.svg.png 2x" data-file-width="512" data-file-height="512" usemap="#ImageMap_1e410522ef8dca5e" /></span><map name="ImageMap_1e410522ef8dca5e"><area href="/info/en/?search=NFPA_704#Blue" shape="poly" coords="23,23,47,47,23,70,0,47" alt="Health 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chloride" title="Health 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chloride" /><area href="/info/en/?search=NFPA_704#Red" shape="poly" coords="47,0,70,23,47,47,23,23" alt="Flammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propane" title="Flammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propane" /><area href="/info/en/?search=NFPA_704#Yellow" shape="poly" coords="70,23,94,47,70,70,47,47" alt="Instability 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g. nitroglycerin" title="Instability 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g. nitroglycerin" /><area href="/info/en/?search=NFPA_704#White" shape="poly" coords="47,47,70,70,47,94,23,70" alt="Special hazards (white): no code" title="Special hazards (white): no code" /></map><figcaption></figcaption></figure></div><div class="nfpa-704-diamond-code nfpa-704-diamond-blue">
<a href="/info/en/?search=NFPA_704#Blue" title="NFPA 704"><span title="Health 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chloride">0</span></a></div><div class="nfpa-704-diamond-code nfpa-704-diamond-red">
<a href="/info/en/?search=NFPA_704#Red" title="NFPA 704"><span title="Flammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propane">4</span></a></div><div class="nfpa-704-diamond-code nfpa-704-diamond-yellow">
<a href="/info/en/?search=NFPA_704#Yellow" title="NFPA 704"><span title="Instability 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g. nitroglycerin">4</span></a></div></div></div></div>
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</tbody></table><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Chemical compound</div>
<h2><span class="mw-headline" id="Biological_role_and_precautions">Biological role and precautions</span><span class="mw-editsection">
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<p>The early lanthanides have been found to be essential to some <a href="/info/en/?search=Methanotrophic" class="mw-redirect" title="Methanotrophic">methanotrophic</a> bacteria living in <a href="/info/en/?search=Mudpot" title="Mudpot">volcanic mudpots</a>, such as <i><a href="/info/en/?search=Methylacidiphilum_fumariolicum" title="Methylacidiphilum fumariolicum">Methylacidiphilum fumariolicum</a></i>: lanthanum, cerium, praseodymium, and neodymium are about equally effective.<sup id="cite_ref-62" class="reference"><a href="#cite_note-62">[61]</a></sup><sup id="cite_ref-63" class="reference"><a href="#cite_note-63">[62]</a></sup> Praseodymium is otherwise not known to have a biological role in any other organisms, but it is not very toxic either. Intravenous injection of rare earths into animals has been known to impair liver function, but the main side effects from inhalation of rare-earth oxides in humans come from radioactive <a href="/info/en/?search=Thorium" title="Thorium">thorium</a> and <a href="/info/en/?search=Uranium" title="Uranium">uranium</a> impurities.<sup id="cite_ref-Ullmann_52-4" class="reference"><a href="#cite_note-Ullmann-52">[51]</a></sup>
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<h2><span class="mw-headline" id="Notes">Notes</span><span class="mw-editsection">
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<li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text">The thermal expansion is highly <a href="/info/en/?search=Anisotropy" title="Anisotropy">anisotropic</a>: the parameters (at 20 °C) for each crystal axis are α<sub><i>a</i></sub> = <span class="nowrap"><span data-sort-value="6994140000000000000♠"></span>1.4<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−6</sup></span>/K, α<sub><i>c</i></sub> = <span class="nowrap"><span data-sort-value="6995108000000000000♠"></span>10.8<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−6</sup></span>/K, and α<sub>average</sub> = α<sub>V</sub>/3 = <span class="nowrap"><span data-sort-value="6994450000000000000♠"></span>4.5<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−6</sup></span>/K.</span>
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<h2><span class="mw-headline" id="References">References</span><span class="mw-editsection">
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<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1215172403">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a{background-size:contain}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a{background-size:contain}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a{background-size:contain}.mw-parser-output .cs1-ws-icon a{background:url("https://upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:#d33}.mw-parser-output .cs1-visible-error{color:#d33}.mw-parser-output .cs1-maint{display:none;color:#2C882D;margin-left:0.3em}.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911F}html.skin-theme-clientpref-night .mw-parser-output .cs1-visible-error,html.skin-theme-clientpref-night .mw-parser-output .cs1-hidden-error{color:#f8a397}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-visible-error,html.skin-theme-clientpref-os .mw-parser-output .cs1-hidden-error{color:#f8a397}html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911F}}</style><cite id="CITEREFReference-OED-praseodymium" class="citation encyclopaedia cs1"><span class="id-lock-subscription" title="Paid subscription required"><a class="external text" href="https://www.oed.com/search/dictionary/?q=praseodymium">"praseodymium"</a></span>. <i><a href="/info/en/?search=Oxford_English_Dictionary" title="Oxford English Dictionary">Oxford English Dictionary</a></i> (Online ed.). <a href="/info/en/?search=Oxford_University_Press" title="Oxford University Press">Oxford University Press</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=praseodymium&rft.btitle=Oxford+English+Dictionary&rft.edition=Online&rft.pub=Oxford+University+Press&rft_id=https%3A%2F%2Fwww.oed.com%2Fsearch%2Fdictionary%2F%3Fq%3Dpraseodymium&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span> <span style="font-size:0.95em; font-size:95%; color: var( --color-subtle, #555 )">(Subscription or <a class="external text" href="https://www.oed.com/public/login/loggingin#withyourlibrary">participating institution membership</a> required.)</span></span>
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<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite class="citation web cs1"><a class="external text" href="https://www.ciaaw.org/praseodymium.htm">"Standard Atomic Weights: Praseodymium"</a>. <a href="/info/en/?search=Commission_on_Isotopic_Abundances_and_Atomic_Weights" title="Commission on Isotopic Abundances and Atomic Weights">CIAAW</a>. 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Standard+Atomic+Weights%3A+Praseodymium&rft.pub=CIAAW&rft.date=2017&rft_id=https%3A%2F%2Fwww.ciaaw.org%2Fpraseodymium.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-CIAAW2021-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-CIAAW2021_3-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFProhaskaIrrgeherBenefieldBöhlke2022" class="citation journal cs1">Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). <a class="external text" href="https://www.degruyter.com/document/doi/10.1515/pac-2019-0603/html">"Standard atomic weights of the elements 2021 (IUPAC Technical Report)"</a>. <i>Pure and Applied Chemistry</i>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1515%2Fpac-2019-0603">10.1515/pac-2019-0603</a>. <a href="/info/en/?search=ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://www.worldcat.org/issn/1365-3075">1365-3075</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Pure+and+Applied+Chemistry&rft.atitle=Standard+atomic+weights+of+the+elements+2021+%28IUPAC+Technical+Report%29&rft.date=2022-05-04&rft_id=info%3Adoi%2F10.1515%2Fpac-2019-0603&rft.issn=1365-3075&rft.aulast=Prohaska&rft.aufirst=Thomas&rft.au=Irrgeher%2C+Johanna&rft.au=Benefield%2C+Jacqueline&rft.au=B%C3%B6hlke%2C+John+K.&rft.au=Chesson%2C+Lesley+A.&rft.au=Coplen%2C+Tyler+B.&rft.au=Ding%2C+Tiping&rft.au=Dunn%2C+Philip+J.+H.&rft.au=Gr%C3%B6ning%2C+Manfred&rft.au=Holden%2C+Norman+E.&rft.au=Meijer%2C+Harro+A.+J.&rft_id=https%3A%2F%2Fwww.degruyter.com%2Fdocument%2Fdoi%2F10.1515%2Fpac-2019-0603%2Fhtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-Arblaster_2018-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-Arblaster_2018_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Arblaster_2018_4-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Arblaster_2018_4-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Arblaster_2018_4-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-Arblaster_2018_4-4"><sup><i><b>e</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFArblaster2018" class="citation book cs1">Arblaster, John W. (2018). <i>Selected Values of the Crystallographic Properties of Elements</i>. Materials Park, Ohio: ASM International. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-1-62708-155-9" title="Special:BookSources/978-1-62708-155-9"><bdi>978-1-62708-155-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Selected+Values+of+the+Crystallographic+Properties+of+Elements&rft.place=Materials+Park%2C+Ohio&rft.pub=ASM+International&rft.date=2018&rft.isbn=978-1-62708-155-9&rft.aulast=Arblaster&rft.aufirst=John+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-Cloke1993-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-Cloke1993_5-0">^</a></b></span> <span class="reference-text">Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFCloke1993" class="citation journal cs1">Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". <i>Chem. Soc. Rev</i>. <b>22</b>: 17–24. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1039%2FCS9932200017">10.1039/CS9932200017</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chem.+Soc.+Rev.&rft.atitle=Zero+Oxidation+State+Compounds+of+Scandium%2C+Yttrium%2C+and+the+Lanthanides&rft.volume=22&rft.pages=17-24&rft.date=1993&rft_id=info%3Adoi%2F10.1039%2FCS9932200017&rft.aulast=Cloke&rft.aufirst=F.+Geoffrey+N.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span> and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFArnoldPetrukhinaBochenkovShabatina2003" class="citation journal cs1">Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (15 December 2003). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". <i>Journal of Organometallic Chemistry</i>. <b>688</b> (1–2): 49–55. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1016%2Fj.jorganchem.2003.08.028">10.1016/j.jorganchem.2003.08.028</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Organometallic+Chemistry&rft.atitle=Arene+complexation+of+Sm%2C+Eu%2C+Tm+and+Yb+atoms%3A+a+variable+temperature+spectroscopic+investigation&rft.volume=688&rft.issue=1%E2%80%932&rft.pages=49-55&rft.date=2003-12-15&rft_id=info%3Adoi%2F10.1016%2Fj.jorganchem.2003.08.028&rft.aulast=Arnold&rft.aufirst=Polly+L.&rft.au=Petrukhina%2C+Marina+A.&rft.au=Bochenkov%2C+Vladimir+E.&rft.au=Shabatina%2C+Tatyana+I.&rft.au=Zagorskii%2C+Vyacheslav+V.&rft.au=Cloke&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFChen2019" class="citation journal cs1">Chen, Xin; et al. (13 December 2019). "Lanthanides with Unusually Low Oxidation States in the PrB<sup>3–</sup> and PrB<sup>4–</sup> Boride Clusters". <i>Inorganic Chemistry</i>. <b>58</b> (1): 411–418. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1021%2Facs.inorgchem.8b02572">10.1021/acs.inorgchem.8b02572</a>. <a href="/info/en/?search=PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/30543295">30543295</a>. <a href="/info/en/?search=S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a class="external text" href="https://api.semanticscholar.org/CorpusID:56148031">56148031</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Inorganic+Chemistry&rft.atitle=Lanthanides+with+Unusually+Low+Oxidation+States+in+the+PrB%3Csup%3E3%E2%80%93%3C%2Fsup%3E+and+PrB%3Csup%3E4%E2%80%93%3C%2Fsup%3E+Boride+Clusters&rft.volume=58&rft.issue=1&rft.pages=411-418&rft.date=2019-12-13&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A56148031%23id-name%3DS2CID&rft_id=info%3Apmid%2F30543295&rft_id=info%3Adoi%2F10.1021%2Facs.inorgchem.8b02572&rft.aulast=Chen&rft.aufirst=Xin&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-jackson-8"><span class="mw-cite-backlink">^ <a href="#cite_ref-jackson_8-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-jackson_8-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFJackson,_M.2000" class="citation journal cs1">Jackson, M. (2000). <a class="external text" href="https://www.irm.umn.edu/quarterly/irmq10-3.pdf">"Magnetism of Rare Earth"</a> <span class="cs1-format">(PDF)</span>. <i>The IRM quarterly</i>. <b>10</b> (3): 1.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+IRM+quarterly&rft.atitle=Magnetism+of+Rare+Earth&rft.volume=10&rft.issue=3&rft.pages=1&rft.date=2000&rft.au=Jackson%2C+M.&rft_id=http%3A%2F%2Fwww.irm.umn.edu%2Fquarterly%2Firmq10-3.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFWeast1984" class="citation book cs1">Weast, Robert (1984). <i>CRC, Handbook of Chemistry and Physics</i>. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/0-8493-0464-4" title="Special:BookSources/0-8493-0464-4"><bdi>0-8493-0464-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=CRC%2C+Handbook+of+Chemistry+and+Physics&rft.place=Boca+Raton%2C+Florida&rft.pages=E110&rft.pub=Chemical+Rubber+Company+Publishing&rft.date=1984&rft.isbn=0-8493-0464-4&rft.aulast=Weast&rft.aufirst=Robert&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-NUBASE2020-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-NUBASE2020_10-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFKondevWangHuangNaimi2021" class="citation journal cs1">Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). <a class="external text" href="https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf">"The NUBASE2020 evaluation of nuclear properties"</a> <span class="cs1-format">(PDF)</span>. <i>Chinese Physics C</i>. <b>45</b> (3): 030001. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1088%2F1674-1137%2Fabddae">10.1088/1674-1137/abddae</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chinese+Physics+C&rft.atitle=The+NUBASE2020+evaluation+of+nuclear+properties&rft.volume=45&rft.issue=3&rft.pages=030001&rft.date=2021&rft_id=info%3Adoi%2F10.1088%2F1674-1137%2Fabddae&rft.aulast=Kondev&rft.aufirst=F.+G.&rft.au=Wang%2C+M.&rft.au=Huang%2C+W.+J.&rft.au=Naimi%2C+S.&rft.au=Audi%2C+G.&rft_id=https%3A%2F%2Fwww-nds.iaea.org%2Famdc%2Fame2020%2FNUBASE2020.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span> </span>
</li>
<li id="cite_note-CRC-11"><span class="mw-cite-backlink">^ <a href="#cite_ref-CRC_11-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-CRC_11-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-CRC_11-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFLide2005" class="citation book cs1">Lide, D. R., ed. (2005). <i>CRC Handbook of Chemistry and Physics</i> (86th ed.). Boca Raton (FL): CRC Press. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/0-8493-0486-5" title="Special:BookSources/0-8493-0486-5"><bdi>0-8493-0486-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=CRC+Handbook+of+Chemistry+and+Physics&rft.place=Boca+Raton+%28FL%29&rft.edition=86th&rft.pub=CRC+Press&rft.date=2005&rft.isbn=0-8493-0486-5&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFClementiRaimondReinhardt1967" class="citation journal cs1">Clementi, E.; Raimond, D. L.; Reinhardt, W. P. (1967). "Atomic Screening Constants from SCF Functions. II. Atoms with 37 to 86 Electrons". <i><a href="/info/en/?search=Journal_of_Chemical_Physics" class="mw-redirect" title="Journal of Chemical Physics">Journal of Chemical Physics</a></i>. <b>47</b> (4): 1300–1307. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/1967JChPh..47.1300C">1967JChPh..47.1300C</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1063%2F1.1712084">10.1063/1.1712084</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Physics&rft.atitle=Atomic+Screening+Constants+from+SCF+Functions.+II.+Atoms+with+37+to+86+Electrons&rft.volume=47&rft.issue=4&rft.pages=1300-1307&rft.date=1967&rft_id=info%3Adoi%2F10.1063%2F1.1712084&rft_id=info%3Abibcode%2F1967JChPh..47.1300C&rft.aulast=Clementi&rft.aufirst=E.&rft.au=Raimond%2C+D.+L.&rft.au=Reinhardt%2C+W.+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFSlater1964" class="citation journal cs1">Slater, J. C. (1964). "Atomic Radii in Crystals". <i><a href="/info/en/?search=Journal_of_Chemical_Physics" class="mw-redirect" title="Journal of Chemical Physics">Journal of Chemical Physics</a></i>. <b>41</b> (10): 3199–3205. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/1964JChPh..41.3199S">1964JChPh..41.3199S</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1063%2F1.1725697">10.1063/1.1725697</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Physics&rft.atitle=Atomic+Radii+in+Crystals&rft.volume=41&rft.issue=10&rft.pages=3199-3205&rft.date=1964&rft_id=info%3Adoi%2F10.1063%2F1.1725697&rft_id=info%3Abibcode%2F1964JChPh..41.3199S&rft.aulast=Slater&rft.aufirst=J.+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Greenwood1235-14"><span class="mw-cite-backlink">^ <a href="#cite_ref-Greenwood1235_14-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Greenwood1235_14-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Greenwood and Earnshaw, pp. 1232–8</span>
</li>
<li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFCullityGraham2011" class="citation book cs1">Cullity, B. D.; Graham, C. D. (2011). <i>Introduction to Magnetic Materials</i>. <a href="/info/en/?search=John_Wiley_%26_Sons" class="mw-redirect" title="John Wiley & Sons">John Wiley & Sons</a>. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-1-118-21149-6" title="Special:BookSources/978-1-118-21149-6"><bdi>978-1-118-21149-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Introduction+to+Magnetic+Materials&rft.pub=John+Wiley+%26+Sons&rft.date=2011&rft.isbn=978-1-118-21149-6&rft.aulast=Cullity&rft.aufirst=B.+D.&rft.au=Graham%2C+C.+D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite class="citation web cs1"><a class="external text" href="https://www.elementsales.com/re_exp/index.htm">"Rare-Earth Metal Long Term Air Exposure Test"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">8 August</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Rare-Earth+Metal+Long+Term+Air+Exposure+Test&rft_id=http%3A%2F%2Fwww.elementsales.com%2Fre_exp%2Findex.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-webelements-17"><span class="mw-cite-backlink">^ <a href="#cite_ref-webelements_17-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-webelements_17-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-webelements_17-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-webelements_17-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite class="citation web cs1"><a class="external text" href="https://www.webelements.com/praseodymium/chemistry.html">"Chemical reactions of Praseodymium"</a>. Webelements<span class="reference-accessdate">. Retrieved <span class="nowrap">9 July</span> 2016</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Chemical+reactions+of+Praseodymium&rft.pub=Webelements&rft_id=https%3A%2F%2Fwww.webelements.com%2Fpraseodymium%2Fchemistry.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Greenwood1238-18"><span class="mw-cite-backlink">^ <a href="#cite_ref-Greenwood1238_18-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Greenwood1238_18-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Greenwood and Earnshaw, pp. 1238–9</span>
</li>
<li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFBrauer,_G.Pfeiffer,_B.1963" class="citation journal cs1">Brauer, G.; Pfeiffer, B. (1963). "Hydrolytische spaltung von höheren oxiden des Praseodyms und des terbiums". <i>Journal of the Less Common Metals</i>. <b>5</b> (2): 171–176. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1016%2F0022-5088%2863%2990010-9">10.1016/0022-5088(63)90010-9</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+Less+Common+Metals&rft.atitle=Hydrolytische+spaltung+von+h%C3%B6heren+oxiden+des+Praseodyms+und+des+terbiums&rft.volume=5&rft.issue=2&rft.pages=171-176&rft.date=1963&rft_id=info%3Adoi%2F10.1016%2F0022-5088%2863%2990010-9&rft.au=Brauer%2C+G.&rft.au=Pfeiffer%2C+B.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFMinasian,_S.G.Batista,_E.R.Booth,_C.H.Clark,_D.L.2017" class="citation journal cs1">Minasian, S.G.; Batista, E.R.; Booth, C.H.; Clark, D.L.; Keith, J.M.; Kozimor, S.A.; Lukens, W.W.; Martin, R.L.; Shuh, D.K.; Stieber, C.E.; Tylisczcak, T.; Wen, Xiao-dong (2017). <a class="external text" href="https://escholarship.org/content/qt4dt0d19b/qt4dt0d19b.pdf?t=p0hj5c">"Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2"</a> <span class="cs1-format">(PDF)</span>. <i>Journal of the American Chemical Society</i>. <b>139</b> (49): 18052–18064. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1021%2Fjacs.7b10361">10.1021/jacs.7b10361</a>. <a href="/info/en/?search=OSTI_(identifier)" class="mw-redirect" title="OSTI (identifier)">OSTI</a> <a class="external text" href="https://www.osti.gov/biblio/1485070">1485070</a>. <a href="/info/en/?search=PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/29182343">29182343</a>. <a href="/info/en/?search=S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a class="external text" href="https://api.semanticscholar.org/CorpusID:5382130">5382130</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+American+Chemical+Society&rft.atitle=Quantitative+Evidence+for+Lanthanide-Oxygen+Orbital+Mixing+in+CeO2%2C+PrO2%2C+and+TbO2&rft.volume=139&rft.issue=49&rft.pages=18052-18064&rft.date=2017&rft_id=info%3Apmid%2F29182343&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A5382130%23id-name%3DS2CID&rft_id=https%3A%2F%2Fwww.osti.gov%2Fbiblio%2F1485070%23id-name%3DOSTI&rft_id=info%3Adoi%2F10.1021%2Fjacs.7b10361&rft.au=Minasian%2C+S.G.&rft.au=Batista%2C+E.R.&rft.au=Booth%2C+C.H.&rft.au=Clark%2C+D.L.&rft.au=Keith%2C+J.M.&rft.au=Kozimor%2C+S.A.&rft.au=Lukens%2C+W.W.&rft.au=Martin%2C+R.L.&rft.au=Shuh%2C+D.K.&rft.au=Stieber%2C+C.E.&rft.au=Tylisczcak%2C+T.&rft.au=Wen%2C+Xiao-dong&rft_id=https%3A%2F%2Fescholarship.org%2Fcontent%2Fqt4dt0d19b%2Fqt4dt0d19b.pdf%3Ft%3Dp0hj5c&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Greenwood643-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood643_21-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, pp. 643–4</span>
</li>
<li id="cite_note-Greenwood1240-22"><span class="mw-cite-backlink">^ <a href="#cite_ref-Greenwood1240_22-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Greenwood1240_22-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Greenwood and Earnshaw, p. 1240–2</span>
</li>
<li id="cite_note-Greenwood1242-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood1242_23-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, pp. 1242–4</span>
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<li id="cite_note-SroorEdelmann2012-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-SroorEdelmann2012_24-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFSroorEdelmann2012" class="citation book cs1">Sroor, Farid M.A.; Edelmann, Frank T. (2012). "Lanthanides: Tetravalent Inorganic". <i>Encyclopedia of Inorganic and Bioinorganic Chemistry</i>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1002%2F9781119951438.eibc2033">10.1002/9781119951438.eibc2033</a>. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-1-119-95143-8" title="Special:BookSources/978-1-119-95143-8"><bdi>978-1-119-95143-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Lanthanides%3A+Tetravalent+Inorganic&rft.btitle=Encyclopedia+of+Inorganic+and+Bioinorganic+Chemistry&rft.date=2012&rft_id=info%3Adoi%2F10.1002%2F9781119951438.eibc2033&rft.isbn=978-1-119-95143-8&rft.aulast=Sroor&rft.aufirst=Farid+M.A.&rft.au=Edelmann%2C+Frank+T.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Greenwood1232-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood1232_25-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, pp. 1232–5</span>
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<li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFHobart,_D.E.Samhoun,_K.Young,_J.P.Norvell,_V.E.1980" class="citation journal cs1">Hobart, D.E.; Samhoun, K.; Young, J.P.; Norvell, V.E.; Mamantov, G.; Peterson, J. R. (1980). "Stabilization of Praseodymium(IV) and Terbium(IV) in Aqueous Carbonate Solution". <i>Inorganic and Nuclear Chemistry Letters</i>. <b>16</b> (5): 321–328. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1016%2F0020-1650%2880%2980069-9">10.1016/0020-1650(80)80069-9</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Inorganic+and+Nuclear+Chemistry+Letters&rft.atitle=Stabilization+of+Praseodymium%28IV%29+and+Terbium%28IV%29+in+Aqueous+Carbonate+Solution&rft.volume=16&rft.issue=5&rft.pages=321-328&rft.date=1980&rft_id=info%3Adoi%2F10.1016%2F0020-1650%2880%2980069-9&rft.au=Hobart%2C+D.E.&rft.au=Samhoun%2C+K.&rft.au=Young%2C+J.P.&rft.au=Norvell%2C+V.E.&rft.au=Mamantov%2C+G.&rft.au=Peterson%2C+J.+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFZhangHuQuSu2016" class="citation journal cs1">Zhang, Qingnan; Hu, Shu-Xian; Qu, Hui; Su, Jing; Wang, Guanjun; Lu, Jun-Bo; Chen, Mohua; Zhou, Mingfei; Li, Jun (6 June 2016). "Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides". <i>Angewandte Chemie International Edition</i>. <b>55</b> (24): 6896–6900. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1002%2Fanie.201602196">10.1002/anie.201602196</a>. <a href="/info/en/?search=ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://www.worldcat.org/issn/1521-3773">1521-3773</a>. <a href="/info/en/?search=PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/27100273">27100273</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Angewandte+Chemie+International+Edition&rft.atitle=Pentavalent+Lanthanide+Compounds%3A+Formation+and+Characterization+of+Praseodymium%28V%29+Oxides&rft.volume=55&rft.issue=24&rft.pages=6896-6900&rft.date=2016-06-06&rft.issn=1521-3773&rft_id=info%3Apmid%2F27100273&rft_id=info%3Adoi%2F10.1002%2Fanie.201602196&rft.aulast=Zhang&rft.aufirst=Qingnan&rft.au=Hu%2C+Shu-Xian&rft.au=Qu%2C+Hui&rft.au=Su%2C+Jing&rft.au=Wang%2C+Guanjun&rft.au=Lu%2C+Jun-Bo&rft.au=Chen%2C+Mohua&rft.au=Zhou%2C+Mingfei&rft.au=Li%2C+Jun&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Greenwood1248-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood1248_28-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, pp. 1248–9</span>
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<li id="cite_note-Greenwood1244-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood1244_29-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, pp. 1244–8</span>
</li>
<li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFWillauer,_A.R.Palumbo,_C.T.Fadaei-Tirani,_F.Zivkovic,_I.2020" class="citation journal cs1">Willauer, A.R.; Palumbo, C.T.; Fadaei-Tirani, F.; Zivkovic, I.; Douair, I.; Maron, L.; Mazzanti, M. (2020). <a class="external text" href="https://infoscience.epfl.ch/record/277306">"Accessing the +IV Oxidation State in Molecular Complexes of Praseodymium"</a>. <i>Journal of the American Chemical Society</i>. <b>142</b> (12): 489–493. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1021%2Fjacs.0c01204">10.1021/jacs.0c01204</a>. <a href="/info/en/?search=PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/32134644">32134644</a>. <a href="/info/en/?search=S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a class="external text" href="https://api.semanticscholar.org/CorpusID:212564931">212564931</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+American+Chemical+Society&rft.atitle=Accessing+the+%2BIV+Oxidation+State+in+Molecular+Complexes+of+Praseodymium.&rft.volume=142&rft.issue=12&rft.pages=489-493&rft.date=2020&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A212564931%23id-name%3DS2CID&rft_id=info%3Apmid%2F32134644&rft_id=info%3Adoi%2F10.1021%2Fjacs.0c01204&rft.au=Willauer%2C+A.R.&rft.au=Palumbo%2C+C.T.&rft.au=Fadaei-Tirani%2C+F.&rft.au=Zivkovic%2C+I.&rft.au=Douair%2C+I.&rft.au=Maron%2C+L.&rft.au=Mazzanti%2C+M.&rft_id=http%3A%2F%2Finfoscience.epfl.ch%2Frecord%2F277306&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Audi-31"><span class="mw-cite-backlink">^ <a href="#cite_ref-Audi_31-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Audi_31-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFAudiBersillonBlachotWapstra2003" class="citation cs2">Audi, Georges; Bersillon, Olivier; Blachot, Jean; <a href="/info/en/?search=Aaldert_Wapstra" title="Aaldert Wapstra">Wapstra, Aaldert Hendrik</a> (2003), <a class="external text" href="https://hal.archives-ouvertes.fr/in2p3-00020241/document">"The N<small>UBASE</small> evaluation of nuclear and decay properties"</a>, <i>Nuclear Physics A</i>, <b>729</b>: 3–128, <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/2003NuPhA.729....3A">2003NuPhA.729....3A</a>, <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1016%2Fj.nuclphysa.2003.11.001">10.1016/j.nuclphysa.2003.11.001</a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nuclear+Physics+A&rft.atitle=The+N%3Csmall%3EUBASE%3C%2Fsmall%3E+evaluation+of+nuclear+and+decay+properties&rft.volume=729&rft.pages=3-128&rft.date=2003&rft_id=info%3Adoi%2F10.1016%2Fj.nuclphysa.2003.11.001&rft_id=info%3Abibcode%2F2003NuPhA.729....3A&rft.aulast=Audi&rft.aufirst=Georges&rft.au=Bersillon%2C+Olivier&rft.au=Blachot%2C+Jean&rft.au=Wapstra%2C+Aaldert+Hendrik&rft_id=https%3A%2F%2Fhal.archives-ouvertes.fr%2Fin2p3-00020241%2Fdocument&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Cameron-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-Cameron_32-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFCameron1973" class="citation journal cs1">Cameron, A. G. W. (1973). <a class="external text" href="https://web.archive.org/web/20111021030549/http://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf">"Abundance of the Elements in the Solar System"</a> <span class="cs1-format">(PDF)</span>. <i>Space Science Reviews</i>. <b>15</b> (1): 121–146. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/1973SSRv...15..121C">1973SSRv...15..121C</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1007%2FBF00172440">10.1007/BF00172440</a>. <a href="/info/en/?search=S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a class="external text" href="https://api.semanticscholar.org/CorpusID:120201972">120201972</a>. Archived from <a class="external text" href="https://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 21 October 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space+Science+Reviews&rft.atitle=Abundance+of+the+Elements+in+the+Solar+System&rft.volume=15&rft.issue=1&rft.pages=121-146&rft.date=1973&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A120201972%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2FBF00172440&rft_id=info%3Abibcode%2F1973SSRv...15..121C&rft.aulast=Cameron&rft.aufirst=A.+G.+W.&rft_id=http%3A%2F%2Fpubs.giss.nasa.gov%2Fdocs%2F1973%2F1973_Cameron_1.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-Emsley120-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-Emsley120_33-0">^</a></b></span> <span class="reference-text">Emsley, pp. 120–5</span>
</li>
<li id="cite_note-Greenwood1424-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood1424_34-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, p. 1424</span>
</li>
<li id="cite_note-XI-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-XI_35-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFWeeks1932" class="citation journal cs1"><a href="/info/en/?search=Mary_Elvira_Weeks" title="Mary Elvira Weeks">Weeks, Mary Elvira</a> (1932). "The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium:Zirconium, Titanium, Cerium and Thorium". <i>The Journal of Chemical Education</i>. <b>9</b> (7): 1231–1243. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/1932JChEd...9.1231W">1932JChEd...9.1231W</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1021%2Fed009p1231">10.1021/ed009p1231</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Journal+of+Chemical+Education&rft.atitle=The+Discovery+of+the+Elements%3A+XI.+Some+Elements+Isolated+with+the+Aid+of+Potassium+and+Sodium%3AZirconium%2C+Titanium%2C+Cerium+and+Thorium&rft.volume=9&rft.issue=7&rft.pages=1231-1243&rft.date=1932&rft_id=info%3Adoi%2F10.1021%2Fed009p1231&rft_id=info%3Abibcode%2F1932JChEd...9.1231W&rft.aulast=Weeks&rft.aufirst=Mary+Elvira&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Weeks-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-Weeks_36-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFWeeks1956" class="citation book cs1">Weeks, Mary Elvira (1956). <a class="external text" href="https://archive.org/details/discoveryoftheel002045mbp"><i>The discovery of the elements</i></a> (6th ed.). Easton, PA: Journal of Chemical Education.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+discovery+of+the+elements&rft.place=Easton%2C+PA&rft.edition=6th&rft.pub=Journal+of+Chemical+Education&rft.date=1956&rft.aulast=Weeks&rft.aufirst=Mary+Elvira&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fdiscoveryoftheel002045mbp&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Virginia-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-Virginia_37-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFMarshallMarshall2015" class="citation journal cs1">Marshall, James L.; Marshall, Virginia R. (Winter 2015). <a class="external text" href="https://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf">"Rediscovery of the elements: The Rare Earths – The Confusing Years"</a> <span class="cs1-format">(PDF)</span>. <i>The Hexagon</i>: 72–77.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Hexagon&rft.atitle=Rediscovery+of+the+elements%3A+The+Rare+Earths+%E2%80%93+The+Confusing+Years&rft.ssn=winter&rft.pages=72-77&rft.date=2015&rft.aulast=Marshall&rft.aufirst=James+L.&rft.au=Marshall%2C+Virginia+R.&rft_id=http%3A%2F%2Fwww.chem.unt.edu%2F~jimm%2FREDISCOVERY%25207-09-2018%2FHexagon%2520Articles%2Frare%2520earths%2520II.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</a></b></span> <span class="reference-text">(Berzelius) (1839) <a class="external text" href="https://archive.org/stream/ComptesRendusAcademieDesSciences0008/ComptesRendusAcadmieDesSciences-Tome008-Janvier-juin1839#page/n361/mode/1up">"Nouveau métal"</a> (New metal), <i>Comptes rendus</i>, <i>8</i> : 356–357. From p. 356: <i>"L'oxide de cérium, extrait de la cérite par la procédé ordinaire, contient à peu près les deux cinquièmes de son poids de l'oxide du nouveau métal qui ne change que peu les propriétés du cérium, et qui s'y tient pour ainsi dire caché. Cette raison a engagé M. Mosander à donner au nouveau métal le nom de </i>Lantane<i>."</i> (The oxide of cerium, extracted from cerite by the usual procedure, contains almost two fifths of its weight in the oxide of the new metal, which differs only slightly from the properties of cerium, and which is held in it so to speak "hidden". This reason motivated Mr. Mosander to give to the new metal the name <i>Lantane</i>.)</span>
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<li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text">(Berzelius) (1839) <a class="external text" href="https://books.google.com/books?id=dF1KiX7MbSMC&pg=PA390">"Latanium — a new metal,"</a> <i>Philosophical Magazine</i>, new series, <b>14</b> : 390–391.</span>
</li>
<li id="cite_note-Lost-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-Lost_40-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="Fontani" class="citation book cs1">Fontani, Marco; Costa, Mariagrazia; Orna, Virginia (2014). <a class="external text" href="https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA122"><i>The Lost Elements: The Periodic Table's Shadow Side</i></a>. Oxford University Press. pp. 122–123. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-0-19-938334-4" title="Special:BookSources/978-0-19-938334-4"><bdi>978-0-19-938334-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Lost+Elements%3A+The+Periodic+Table%27s+Shadow+Side&rft.pages=122-123&rft.pub=Oxford+University+Press&rft.date=2014&rft.isbn=978-0-19-938334-4&rft.aulast=Fontani&rft.aufirst=Marco&rft.au=Costa%2C+Mariagrazia&rft.au=Orna%2C+Virginia&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DCk9jBAAAQBAJ%26pg%3DPA122&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-Greenwood1229-41"><span class="mw-cite-backlink">^ <a href="#cite_ref-Greenwood1229_41-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Greenwood1229_41-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Greenwood1229_41-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Greenwood1229_41-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-Greenwood1229_41-4"><sup><i><b>e</b></i></sup></a></span> <span class="reference-text">Greenwood and Earnshaw, p. 1229–32</span>
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<li id="cite_note-Lost_p40-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-Lost_p40_42-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="Fontani" class="citation book cs1">Fontani, Marco; Costa, Mariagrazia; Orna, Virginia (2014). <a class="external text" href="https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA40"><i>The Lost Elements: The Periodic Table's Shadow Side</i></a>. Oxford University Press. p. 40. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-0-19-938334-4" title="Special:BookSources/978-0-19-938334-4"><bdi>978-0-19-938334-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Lost+Elements%3A+The+Periodic+Table%27s+Shadow+Side&rft.pages=40&rft.pub=Oxford+University+Press&rft.date=2014&rft.isbn=978-0-19-938334-4&rft.aulast=Fontani&rft.aufirst=Marco&rft.au=Costa%2C+Mariagrazia&rft.au=Orna%2C+Virginia&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DCk9jBAAAQBAJ%26pg%3DPA40&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-CRC97-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-CRC97_43-0">^</a></b></span> <span class="reference-text">Abundance of Elements in the Earth's Crust and in the Sea, <i>CRC Handbook of Chemistry and Physics,</i> 97th edition (2016–2017), p. 14-17</span>
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<li id="cite_note-patnaik-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-patnaik_44-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFPatnaik2003" class="citation book cs1">Patnaik, Pradyot (2003). <a class="external text" href="https://books.google.com/books?id=Xqj-TTzkvTEC&pg=PA243"><i>Handbook of Inorganic Chemical Compounds</i></a>. McGraw-Hill. pp. 444–446. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-0-07-049439-8" title="Special:BookSources/978-0-07-049439-8"><bdi>978-0-07-049439-8</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">6 June</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Handbook+of+Inorganic+Chemical+Compounds&rft.pages=444-446&rft.pub=McGraw-Hill&rft.date=2003&rft.isbn=978-0-07-049439-8&rft.aulast=Patnaik&rft.aufirst=Pradyot&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DXqj-TTzkvTEC%26pg%3DPA243&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-45">^</a></b></span> <span class="reference-text">
<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFHudson_Institute_of_Mineralogy1993–2018" class="citation web cs1">Hudson Institute of Mineralogy (1993–2018). <a class="external text" href="https://www.mindat.org/">"Mindat.org"</a>. <i>www.mindat.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">14 January</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.mindat.org&rft.atitle=Mindat.org&rft.date=1993%2F2018&rft.au=Hudson+Institute+of+Mineralogy&rft_id=https%3A%2F%2Fwww.mindat.org%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-Patnaik-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-Patnaik_46-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFPatnaik2007">Patnaik 2007</a>, pp. <a class="external text" href="https://books.google.com/books?id=-CRRJBVv5d0C&pg=PA478">478–479</a><span class="error harv-error" style="display: none; font-size:100%"> harvnb error: no target: CITEREFPatnaik2007 (<a href="/info/en/?search=Category:Harv_and_Sfn_template_errors" title="Category:Harv and Sfn template errors">help</a>)</span>.</span>
</li>
<li id="cite_note-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-47">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFKreidl1942" class="citation journal cs1">Kreidl, Norbert J. (1942). "RARE EARTHS*". <i>Journal of the American Ceramic Society</i>. <b>25</b> (5): 141–143. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1111%2Fj.1151-2916.1942.tb14363.x">10.1111/j.1151-2916.1942.tb14363.x</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+American+Ceramic+Society&rft.atitle=RARE+EARTHS%2A&rft.volume=25&rft.issue=5&rft.pages=141-143&rft.date=1942&rft_id=info%3Adoi%2F10.1111%2Fj.1151-2916.1942.tb14363.x&rft.aulast=Kreidl&rft.aufirst=Norbert+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFJhaNaftalyJorderySamson1995" class="citation journal cs1">Jha, A.; Naftaly, M.; Jordery, S.; Samson, B. N.; et al. (1995). <a class="external text" href="https://eprints.soton.ac.uk/78174/1/918.pdf">"Design and fabrication of Pr3+-doped fluoride glass optical fibres for efficient 1.3 mu m amplifiers"</a> <span class="cs1-format">(PDF)</span>. <i>Pure and Applied Optics: Journal of the European Optical Society Part A</i>. <b>4</b> (4): 417. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/1995PApOp...4..417J">1995PApOp...4..417J</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1088%2F0963-9659%2F4%2F4%2F019">10.1088/0963-9659/4/4/019</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Pure+and+Applied+Optics%3A+Journal+of+the+European+Optical+Society+Part+A&rft.atitle=Design+and+fabrication+of+Pr3%2B-doped+fluoride+glass+optical+fibres+for+efficient+1.3+mu+m+amplifiers&rft.volume=4&rft.issue=4&rft.pages=417&rft.date=1995&rft_id=info%3Adoi%2F10.1088%2F0963-9659%2F4%2F4%2F019&rft_id=info%3Abibcode%2F1995PApOp...4..417J&rft.aulast=Jha&rft.aufirst=A.&rft.au=Naftaly%2C+M.&rft.au=Jordery%2C+S.&rft.au=Samson%2C+B.+N.&rft.au=Taylor%2C+E.+R.&rft.au=Hewak%2C+D.&rft.au=Payne%2C+D.+N.&rft.au=Poulain%2C+M.&rft.au=Zhang%2C+G.&rft_id=https%3A%2F%2Feprints.soton.ac.uk%2F78174%2F1%2F918.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFSmartHannaTropperDavey1991" class="citation journal cs1">Smart, R.G.; Hanna, D.C.; Tropper, A.C.; Davey, S.T.; Carter, S.F.; Szebesta, D. (1991). <a class="external text" href="https://digital-library.theiet.org/content/journals/10.1049/el_19910817">"Cw room temperature upconversion lasing at blue, green and red wavelengths in infrared-pumped Pr3+-doped fluoride fibre"</a>. <i>Electronics Letters</i>. <b>27</b> (14): 1307. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/1991ElL....27.1307S">1991ElL....27.1307S</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1049%2Fel%3A19910817">10.1049/el:19910817</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Electronics+Letters&rft.atitle=Cw+room+temperature+upconversion+lasing+at+blue%2C+green+and+red+wavelengths+in+infrared-pumped+Pr3%2B-doped+fluoride+fibre&rft.volume=27&rft.issue=14&rft.pages=1307&rft.date=1991&rft_id=info%3Adoi%2F10.1049%2Fel%3A19910817&rft_id=info%3Abibcode%2F1991ElL....27.1307S&rft.aulast=Smart&rft.aufirst=R.G.&rft.au=Hanna%2C+D.C.&rft.au=Tropper%2C+A.C.&rft.au=Davey%2C+S.T.&rft.au=Carter%2C+S.F.&rft.au=Szebesta%2C+D.&rft_id=https%3A%2F%2Fdigital-library.theiet.org%2Fcontent%2Fjournals%2F10.1049%2Fel_19910817&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFde_PrinseKaramiMoffattPayten2021" class="citation journal cs1">de Prinse, Thomas J.; Karami, Afshin; Moffatt, Jillian E.; Payten, Thomas B.; Tsiminis, Georgios; Teixeira, Lewis Da Silva; Bi, Jingxiu; Kee, Tak W.; Klantsataya, Elizaveta; Sumby, Christopher J.; Spooner, Nigel A. (2021). <a class="external text" href="https://onlinelibrary.wiley.com/doi/10.1002/adom.202001903">"Dual Laser Study of Non‐Degenerate Two Wavelength Upconversion Demonstrated in Sensitizer‐Free NaYF 4 :Pr Nanoparticles"</a>. <i>Advanced Optical Materials</i>. <b>9</b> (7): 2001903. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1002%2Fadom.202001903">10.1002/adom.202001903</a>. <a href="/info/en/?search=Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://hdl.handle.net/2440%2F139814">2440/139814</a></span>. <a href="/info/en/?search=ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://www.worldcat.org/issn/2195-1071">2195-1071</a>. <a href="/info/en/?search=S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a class="external text" href="https://api.semanticscholar.org/CorpusID:234059121">234059121</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Advanced+Optical+Materials&rft.atitle=Dual+Laser+Study+of+Non%E2%80%90Degenerate+Two+Wavelength+Upconversion+Demonstrated+in+Sensitizer%E2%80%90Free+NaYF+4+%3APr+Nanoparticles&rft.volume=9&rft.issue=7&rft.pages=2001903&rft.date=2021&rft_id=info%3Ahdl%2F2440%2F139814&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A234059121%23id-name%3DS2CID&rft.issn=2195-1071&rft_id=info%3Adoi%2F10.1002%2Fadom.202001903&rft.aulast=de+Prinse&rft.aufirst=Thomas+J.&rft.au=Karami%2C+Afshin&rft.au=Moffatt%2C+Jillian+E.&rft.au=Payten%2C+Thomas+B.&rft.au=Tsiminis%2C+Georgios&rft.au=Teixeira%2C+Lewis+Da+Silva&rft.au=Bi%2C+Jingxiu&rft.au=Kee%2C+Tak+W.&rft.au=Klantsataya%2C+Elizaveta&rft.au=Sumby%2C+Christopher+J.&rft.au=Spooner%2C+Nigel+A.&rft_id=https%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fadom.202001903&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
</li>
<li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFKolesovReuterXiaStöhr2011" class="citation journal cs1">Kolesov, Roman; Reuter, Rolf; Xia, Kangwei; Stöhr, Rainer; Zappe, Andrea; Wrachtrup, Jörg (31 October 2011). <a class="external text" href="https://link.aps.org/doi/10.1103/PhysRevB.84.153413">"Super-resolution upconversion microscopy of praseodymium-doped yttrium aluminum garnet nanoparticles"</a>. <i>Physical Review B</i>. <b>84</b> (15): 153413. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/2011PhRvB..84o3413K">2011PhRvB..84o3413K</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1103%2FPhysRevB.84.153413">10.1103/PhysRevB.84.153413</a>. <a href="/info/en/?search=ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://www.worldcat.org/issn/1098-0121">1098-0121</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+B&rft.atitle=Super-resolution+upconversion+microscopy+of+praseodymium-doped+yttrium+aluminum+garnet+nanoparticles&rft.volume=84&rft.issue=15&rft.pages=153413&rft.date=2011-10-31&rft.issn=1098-0121&rft_id=info%3Adoi%2F10.1103%2FPhysRevB.84.153413&rft_id=info%3Abibcode%2F2011PhRvB..84o3413K&rft.aulast=Kolesov&rft.aufirst=Roman&rft.au=Reuter%2C+Rolf&rft.au=Xia%2C+Kangwei&rft.au=St%C3%B6hr%2C+Rainer&rft.au=Zappe%2C+Andrea&rft.au=Wrachtrup%2C+J%C3%B6rg&rft_id=https%3A%2F%2Flink.aps.org%2Fdoi%2F10.1103%2FPhysRevB.84.153413&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-Ullmann-52"><span class="mw-cite-backlink">^ <a href="#cite_ref-Ullmann_52-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Ullmann_52-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Ullmann_52-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Ullmann_52-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-Ullmann_52-4"><sup><i><b>e</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFMcGill" class="citation encyclopaedia cs1">McGill, Ian. "Rare Earth Elements". <i><a href="/info/en/?search=Ullmann%27s_Encyclopedia_of_Industrial_Chemistry" title="Ullmann's Encyclopedia of Industrial Chemistry">Ullmann's Encyclopedia of Industrial Chemistry</a></i>. Vol. 31. Weinheim: Wiley-VCH. p. 183–227. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1002%2F14356007.a22_607">10.1002/14356007.a22_607</a>. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-3527306732" title="Special:BookSources/978-3527306732"><bdi>978-3527306732</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Rare+Earth+Elements&rft.btitle=Ullmann%27s+Encyclopedia+of+Industrial+Chemistry&rft.place=Weinheim&rft.pages=183-227&rft.pub=Wiley-VCH&rft_id=info%3Adoi%2F10.1002%2F14356007.a22_607&rft.isbn=978-3527306732&rft.aulast=McGill&rft.aufirst=Ian&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-ANUPressStopLight-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-ANUPressStopLight_53-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite class="citation web cs1"><a class="external text" href="https://info.anu.edu.au/ovc/Media/Media_Releases/2005/August/290805_stop_light">"ANU team stops light in quantum leap"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">18 May</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=ANU+team+stops+light+in+quantum+leap&rft_id=http%3A%2F%2Finfo.anu.edu.au%2Fovc%2FMedia%2FMedia_Releases%2F2005%2FAugust%2F290805_stop_light&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-IAMGOLD-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-IAMGOLD_54-0">^</a></b></span> <span class="reference-text"><a class="external text" href="https://www.iamgold.com/files/REE101_April_2012.pdf">Rare Earth Elements 101</a> <a class="external text" href="https://web.archive.org/web/20131122140504/http://www.iamgold.com/files/REE101_April_2012.pdf">Archived</a> 2013-11-22 at the <a href="/info/en/?search=Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, IAMGOLD Corporation, April 2012, pp. 5, 7.</span>
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<li id="cite_note-Emsley423-55"><span class="mw-cite-backlink">^ <a href="#cite_ref-Emsley423_55-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Emsley423_55-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Emsley, pp. 423–5</span>
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<li id="cite_note-56"><span class="mw-cite-backlink"><b><a href="#cite_ref-56">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFRokhlin2003" class="citation book cs1">Rokhlin, L. L. (2003). <i>Magnesium alloys containing rare earth metals: structure and properties</i>. CRC Press. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-0-415-28414-1" title="Special:BookSources/978-0-415-28414-1"><bdi>978-0-415-28414-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Magnesium+alloys+containing+rare+earth+metals%3A+structure+and+properties&rft.pub=CRC+Press&rft.date=2003&rft.isbn=978-0-415-28414-1&rft.aulast=Rokhlin&rft.aufirst=L.+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-57"><span class="mw-cite-backlink"><b><a href="#cite_ref-57">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFSuseelan_NairMittal1988" class="citation journal cs1">Suseelan Nair, K.; Mittal, M. C. (1988). "Rare Earths in Magnesium Alloys". <i>Materials Science Forum</i>. <b>30</b>: 89–104. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.4028%2Fwww.scientific.net%2FMSF.30.89">10.4028/www.scientific.net/MSF.30.89</a>. <a href="/info/en/?search=S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a class="external text" href="https://api.semanticscholar.org/CorpusID:136992837">136992837</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Materials+Science+Forum&rft.atitle=Rare+Earths+in+Magnesium+Alloys&rft.volume=30&rft.pages=89-104&rft.date=1988&rft_id=info%3Adoi%2F10.4028%2Fwww.scientific.net%2FMSF.30.89&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A136992837%23id-name%3DS2CID&rft.aulast=Suseelan+Nair&rft.aufirst=K.&rft.au=Mittal%2C+M.+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-58"><span class="mw-cite-backlink"><b><a href="#cite_ref-58">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFBorchert,_Y.Sonstrom,_P.Wilhelm,_M.Borchert,_H.2008" class="citation journal cs1">Borchert, Y.; Sonstrom, P.; Wilhelm, M.; Borchert, H.; et al. (2008). "Nanostructured Praseodymium Oxide: Preparation, Structure, and Catalytic Properties". <i>Journal of Physical Chemistry C</i>. <b>112</b> (8): 3054. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1021%2Fjp0768524">10.1021/jp0768524</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Physical+Chemistry+C&rft.atitle=Nanostructured+Praseodymium+Oxide%3A+Preparation%2C+Structure%2C+and+Catalytic+Properties&rft.volume=112&rft.issue=8&rft.pages=3054&rft.date=2008&rft_id=info%3Adoi%2F10.1021%2Fjp0768524&rft.au=Borchert%2C+Y.&rft.au=Sonstrom%2C+P.&rft.au=Wilhelm%2C+M.&rft.au=Borchert%2C+H.&rft.au=Baumer%2C+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-59"><span class="mw-cite-backlink"><b><a href="#cite_ref-59">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFOverland2019" class="citation journal cs1">Overland, Indra (1 March 2019). <a class="external text" href="https://doi.org/10.1016%2Fj.erss.2018.10.018">"The geopolitics of renewable energy: Debunking four emerging myths"</a>. <i>Energy Research & Social Science</i>. <b>49</b>: 36–40. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://doi.org/10.1016%2Fj.erss.2018.10.018">10.1016/j.erss.2018.10.018</a></span>. <a href="/info/en/?search=ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://www.worldcat.org/issn/2214-6296">2214-6296</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Energy+Research+%26+Social+Science&rft.atitle=The+geopolitics+of+renewable+energy%3A+Debunking+four+emerging+myths&rft.volume=49&rft.pages=36-40&rft.date=2019-03-01&rft_id=info%3Adoi%2F10.1016%2Fj.erss.2018.10.018&rft.issn=2214-6296&rft.aulast=Overland&rft.aufirst=Indra&rft_id=https%3A%2F%2Fdoi.org%2F10.1016%252Fj.erss.2018.10.018&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-Klinger-60"><span class="mw-cite-backlink"><b><a href="#cite_ref-Klinger_60-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFKlinger2017" class="citation book cs1">Klinger, Julie Michelle (2017). <i>Rare earth frontiers : from terrestrial subsoils to lunar landscapes</i>. Ithaca, NY: Cornell University Press. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-1501714603" title="Special:BookSources/978-1501714603"><bdi>978-1501714603</bdi></a>. <a href="/info/en/?search=JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a class="external text" href="https://www.jstor.org/stable/10.7591/j.ctt1w0dd6d">10.7591/j.ctt1w0dd6d</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Rare+earth+frontiers+%3A+from+terrestrial+subsoils+to+lunar+landscapes&rft.place=Ithaca%2C+NY&rft.pub=Cornell+University+Press&rft.date=2017&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F10.7591%2Fj.ctt1w0dd6d%23id-name%3DJSTOR&rft.isbn=978-1501714603&rft.aulast=Klinger&rft.aufirst=Julie+Michelle&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-61"><span class="mw-cite-backlink"><b><a href="#cite_ref-61">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite class="citation web cs1"><a class="external text" href="https://www.sigmaaldrich.com/catalog/product/aldrich/261173?lang=en&region=US">"Praseodymium 261173"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Praseodymium+261173&rft_id=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F261173%3Flang%3Den%26region%3DUS&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-62"><span class="mw-cite-backlink"><b><a href="#cite_ref-62">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFPolBarendsDietlKhadem2013" class="citation journal cs1">Pol, Arjan; Barends, Thomas R. M.; Dietl, Andreas; Khadem, Ahmad F.; Eygensteyn, Jelle; Jetten, Mike S. M.; Op Den Camp, Huub J. M. (2013). "Rare earth metals are essential for methanotrophic life in volcanic mudpots". <i>Environmental Microbiology</i>. <b>16</b> (1): 255–64. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1111%2F1462-2920.12249">10.1111/1462-2920.12249</a>. <a href="/info/en/?search=PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/24034209">24034209</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Environmental+Microbiology&rft.atitle=Rare+earth+metals+are+essential+for+methanotrophic+life+in+volcanic+mudpots&rft.volume=16&rft.issue=1&rft.pages=255-64&rft.date=2013&rft_id=info%3Adoi%2F10.1111%2F1462-2920.12249&rft_id=info%3Apmid%2F24034209&rft.aulast=Pol&rft.aufirst=Arjan&rft.au=Barends%2C+Thomas+R.+M.&rft.au=Dietl%2C+Andreas&rft.au=Khadem%2C+Ahmad+F.&rft.au=Eygensteyn%2C+Jelle&rft.au=Jetten%2C+Mike+S.+M.&rft.au=Op+Den+Camp%2C+Huub+J.+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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<li id="cite_note-63"><span class="mw-cite-backlink"><b><a href="#cite_ref-63">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFKangShenJin2000" class="citation journal cs1">Kang, L.; Shen, Z.; Jin, C. (2000). "Neodymium cations Nd<sup>3+</sup> were transported to the interior of <i>Euglena gracilis</i>". <i>Chin. Sci. Bull</i>. <b>45</b> (277): 585–592. <a href="/info/en/?search=Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/2000ChSBu..45..585K">2000ChSBu..45..585K</a>. <a href="/info/en/?search=Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1007%2FBF02886032">10.1007/BF02886032</a>. <a href="/info/en/?search=S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a class="external text" href="https://api.semanticscholar.org/CorpusID:95983365">95983365</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chin.+Sci.+Bull.&rft.atitle=Neodymium+cations+Nd%3Csup%3E3%2B%3C%2Fsup%3E+were+transported+to+the+interior+of+Euglena+gracilis&rft.volume=45&rft.issue=277&rft.pages=585-592&rft.date=2000&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A95983365%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2FBF02886032&rft_id=info%3Abibcode%2F2000ChSBu..45..585K&rft.aulast=Kang&rft.aufirst=L.&rft.au=Shen%2C+Z.&rft.au=Jin%2C+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></span>
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</ol></div>
<h2><span class="mw-headline" id="Bibliography">Bibliography</span><span class="mw-editsection">
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href="https://en.wikipedia.org/?title=Praseodymium&action=edit&section=11"title="Edit section: Bibliography"
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<ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFEmsley,_John2011" class="citation book cs1">Emsley, John (2011). <i>Nature's Building Blocks: An A-Z Guide to the Elements</i>. <a href="/info/en/?search=Oxford_University_Press" title="Oxford University Press">Oxford University Press</a>. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-0-19-960563-7" title="Special:BookSources/978-0-19-960563-7"><bdi>978-0-19-960563-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Nature%27s+Building+Blocks%3A+An+A-Z+Guide+to+the+Elements&rft.pub=Oxford+University+Press&rft.date=2011&rft.isbn=978-0-19-960563-7&rft.au=Emsley%2C+John&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></li>
<li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1215172403"><cite id="CITEREFGreenwoodEarnshaw1997" class="citation book cs1"><a href="/info/en/?search=Norman_Greenwood" title="Norman Greenwood">Greenwood, Norman N.</a>; Earnshaw, Alan (1997). <i>Chemistry of the Elements</i> (2nd ed.). <a href="/info/en/?search=Butterworth-Heinemann" title="Butterworth-Heinemann">Butterworth-Heinemann</a>. <a href="/info/en/?search=ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/info/en/?search=Special:BookSources/978-0-08-037941-8" title="Special:BookSources/978-0-08-037941-8"><bdi>978-0-08-037941-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Chemistry+of+the+Elements&rft.edition=2nd&rft.pub=Butterworth-Heinemann&rft.date=1997&rft.isbn=978-0-08-037941-8&rft.aulast=Greenwood&rft.aufirst=Norman+N.&rft.au=Earnshaw%2C+Alan&rfr_id=info%3Asid%2Fen.wikipedia.org%3APraseodymium" class="Z3988"></span></li></ul>
<h2><span class="mw-headline" id="Further_reading">Further reading</span><span class="mw-editsection">
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href="https://en.wikipedia.org/?title=Praseodymium&action=edit&section=12"title="Edit section: Further reading"
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<ul><li>R. J. Callow, <i>The Industrial Chemistry of the Lanthanons, Yttrium, Thorium, and Uranium</i>, Pergamon Press, 1967.</li>
<li>Bouhani, H (2020). "Engineering the magnetocaloric properties of PrVO3 epitaxial oxide thin films by strain effects". Applied Physics Letters. 117 (7). arXiv:2008.09193. doi:10.1063/5.0021031.</li></ul>
<h2><span class="mw-headline" id="External_links">External links</span><span class="mw-editsection">
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href="https://en.wikipedia.org/?title=Praseodymium&action=edit&section=13"title="Edit section: External links"
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<ul><li><a class="external text" href="https://www.webelements.com/webelements/elements/text/Pr/index.html">WebElements.com—Praseodymium</a></li>
<li><a class="external text" href="https://education.jlab.org/itselemental/ele059.html">It's Elemental—The Element Praseodymium</a></li></ul>
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<div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1061467846">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}</style></div><div role="navigation" class="navbox" aria-labelledby="Periodic_table" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1063604349"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/info/en/?search=Template:Periodic_table_(navbox)" title="Template:Periodic table (navbox)"><abbr title="View this template" style=";;background:none transparent;border:none;box-shadow:none;padding:0;">v</abbr></a></li><li class="nv-talk"><a href="/info/en/?search=Template_talk:Periodic_table_(navbox)" title="Template talk:Periodic table (navbox)"><abbr title="Discuss this template" style=";;background:none transparent;border:none;box-shadow:none;padding:0;">t</abbr></a></li><li class="nv-edit"><a href="/info/en/?search=Special:EditPage/Template:Periodic_table_(navbox)" title="Special:EditPage/Template:Periodic table (navbox)"><abbr title="Edit this template" style=";;background:none transparent;border:none;box-shadow:none;padding:0;">e</abbr></a></li></ul></div><div id="Periodic_table" style="font-size:114%;margin:0 4em"><a href="/info/en/?search=Periodic_table" title="Periodic table">Periodic table</a></div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd wraplinks" style="width:100%;padding:0"><div style="padding:0 0.25em">
<table style="table-layout:fixed; width:100%;" aria-describedby="periodic-table-legend">
<tbody><tr>
<td style="line-height:100%;">
</td>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Alkali_metal" title="Alkali metal">1</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Alkaline_earth_metal" title="Alkaline earth metal">2</a>
</th>
<td colspan="14">
</td>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_3_element" title="Group 3 element">3</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_4_element" title="Group 4 element">4</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_5_element" title="Group 5 element">5</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_6_element" title="Group 6 element">6</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_7_element" title="Group 7 element">7</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_8_element" title="Group 8 element">8</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_9_element" title="Group 9 element">9</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_10_element" title="Group 10 element">10</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_11_element" title="Group 11 element">11</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Group_12_element" title="Group 12 element">12</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Boron_group" title="Boron group">13</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Carbon_group" title="Carbon group">14</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Pnictogen" title="Pnictogen">15</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Chalcogen" title="Chalcogen">16</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Halogen" title="Halogen">17</a>
</th>
<th scope="col" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Noble_gas" title="Noble gas">18</a>
</th></tr>
<tr>
<th scope="row" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Period_1_element" title="Period 1 element">1</a>
</th>
<td title="H, Hydrogen" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Hydrogen" title="Hydrogen"><span style="display:block">H</span></a></span>
</td>
<td colspan="30">
</td>
<td title="He, Helium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Helium" title="Helium"><span style="display:block">He</span></a></span>
</td></tr>
<tr>
<th scope="row" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Period_2_element" title="Period 2 element">2</a>
</th>
<td title="Li, Lithium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Lithium" title="Lithium"><span style="display:block">Li</span></a></span>
</td>
<td title="Be, Beryllium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Beryllium" title="Beryllium"><span style="display:block">Be</span></a></span>
</td>
<td colspan="24">
</td>
<td title="B, Boron" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Boron" title="Boron"><span style="display:block">B</span></a></span>
</td>
<td title="C, Carbon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Carbon" title="Carbon"><span style="display:block">C</span></a></span>
</td>
<td title="N, Nitrogen" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Nitrogen" title="Nitrogen"><span style="display:block">N</span></a></span>
</td>
<td title="O, Oxygen" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Oxygen" title="Oxygen"><span style="display:block">O</span></a></span>
</td>
<td title="F, Fluorine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Fluorine" title="Fluorine"><span style="display:block">F</span></a></span>
</td>
<td title="Ne, Neon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Neon" title="Neon"><span style="display:block">Ne</span></a></span>
</td></tr>
<tr>
<th scope="row" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Period_3_element" title="Period 3 element">3</a>
</th>
<td title="Na, Sodium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Sodium" title="Sodium"><span style="display:block">Na</span></a></span>
</td>
<td title="Mg, Magnesium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Magnesium" title="Magnesium"><span style="display:block">Mg</span></a></span>
</td>
<td colspan="24">
</td>
<td title="Al, Aluminium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Aluminium" title="Aluminium"><span style="display:block">Al</span></a></span>
</td>
<td title="Si, Silicon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Silicon" title="Silicon"><span style="display:block">Si</span></a></span>
</td>
<td title="P, Phosphorus" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Phosphorus" title="Phosphorus"><span style="display:block">P</span></a></span>
</td>
<td title="S, Sulfur" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Sulfur" title="Sulfur"><span style="display:block">S</span></a></span>
</td>
<td title="Cl, Chlorine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Chlorine" title="Chlorine"><span style="display:block">Cl</span></a></span>
</td>
<td title="Ar, Argon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Argon" title="Argon"><span style="display:block">Ar</span></a></span>
</td></tr>
<tr>
<th scope="row" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Period_4_element" title="Period 4 element">4</a>
</th>
<td title="K, Potassium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Potassium" title="Potassium"><span style="display:block">K</span></a></span>
</td>
<td title="Ca, Calcium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Calcium" title="Calcium"><span style="display:block">Ca</span></a></span>
</td>
<td colspan="14">
</td>
<td title="Sc, Scandium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Scandium" title="Scandium"><span style="display:block">Sc</span></a></span>
</td>
<td title="Ti, Titanium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Titanium" title="Titanium"><span style="display:block">Ti</span></a></span>
</td>
<td title="V, Vanadium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Vanadium" title="Vanadium"><span style="display:block">V</span></a></span>
</td>
<td title="Cr, Chromium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Chromium" title="Chromium"><span style="display:block">Cr</span></a></span>
</td>
<td title="Mn, Manganese" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Manganese" title="Manganese"><span style="display:block">Mn</span></a></span>
</td>
<td title="Fe, Iron" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Iron" title="Iron"><span style="display:block">Fe</span></a></span>
</td>
<td title="Co, Cobalt" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Cobalt" title="Cobalt"><span style="display:block">Co</span></a></span>
</td>
<td title="Ni, Nickel" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Nickel" title="Nickel"><span style="display:block">Ni</span></a></span>
</td>
<td title="Cu, Copper" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Copper" title="Copper"><span style="display:block">Cu</span></a></span>
</td>
<td title="Zn, Zinc" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Zinc" title="Zinc"><span style="display:block">Zn</span></a></span>
</td>
<td title="Ga, Gallium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Gallium" title="Gallium"><span style="display:block">Ga</span></a></span>
</td>
<td title="Ge, Germanium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Germanium" title="Germanium"><span style="display:block">Ge</span></a></span>
</td>
<td title="As, Arsenic" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Arsenic" title="Arsenic"><span style="display:block">As</span></a></span>
</td>
<td title="Se, Selenium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Selenium" title="Selenium"><span style="display:block">Se</span></a></span>
</td>
<td title="Br, Bromine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Bromine" title="Bromine"><span style="display:block">Br</span></a></span>
</td>
<td title="Kr, Krypton" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Krypton" title="Krypton"><span style="display:block">Kr</span></a></span>
</td></tr>
<tr>
<th scope="row" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Period_5_element" title="Period 5 element">5</a>
</th>
<td title="Rb, Rubidium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Rubidium" title="Rubidium"><span style="display:block">Rb</span></a></span>
</td>
<td title="Sr, Strontium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Strontium" title="Strontium"><span style="display:block">Sr</span></a></span>
</td>
<td colspan="14">
</td>
<td title="Y, Yttrium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Yttrium" title="Yttrium"><span style="display:block">Y</span></a></span>
</td>
<td title="Zr, Zirconium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Zirconium" title="Zirconium"><span style="display:block">Zr</span></a></span>
</td>
<td title="Nb, Niobium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Niobium" title="Niobium"><span style="display:block">Nb</span></a></span>
</td>
<td title="Mo, Molybdenum" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Molybdenum" title="Molybdenum"><span style="display:block">Mo</span></a></span>
</td>
<td title="Tc, Technetium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Technetium" title="Technetium"><span style="display:block">Tc</span></a></span>
</td>
<td title="Ru, Ruthenium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Ruthenium" title="Ruthenium"><span style="display:block">Ru</span></a></span>
</td>
<td title="Rh, Rhodium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Rhodium" title="Rhodium"><span style="display:block">Rh</span></a></span>
</td>
<td title="Pd, Palladium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Palladium" title="Palladium"><span style="display:block">Pd</span></a></span>
</td>
<td title="Ag, Silver" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Silver" title="Silver"><span style="display:block">Ag</span></a></span>
</td>
<td title="Cd, Cadmium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Cadmium" title="Cadmium"><span style="display:block">Cd</span></a></span>
</td>
<td title="In, Indium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Indium" title="Indium"><span style="display:block">In</span></a></span>
</td>
<td title="Sn, Tin" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Tin" title="Tin"><span style="display:block">Sn</span></a></span>
</td>
<td title="Sb, Antimony" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Antimony" title="Antimony"><span style="display:block">Sb</span></a></span>
</td>
<td title="Te, Tellurium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Tellurium" title="Tellurium"><span style="display:block">Te</span></a></span>
</td>
<td title="I, Iodine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Iodine" title="Iodine"><span style="display:block">I</span></a></span>
</td>
<td title="Xe, Xenon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Xenon" title="Xenon"><span style="display:block">Xe</span></a></span>
</td></tr>
<tr>
<th scope="row" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Period_6_element" title="Period 6 element">6</a>
</th>
<td title="Cs, Caesium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Caesium" title="Caesium"><span style="display:block">Cs</span></a></span>
</td>
<td title="Ba, Barium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Barium" title="Barium"><span style="display:block">Ba</span></a></span>
</td>
<td title="La, Lanthanum" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Lanthanum" title="Lanthanum"><span style="display:block">La</span></a></span>
</td>
<td title="Ce, Cerium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Cerium" title="Cerium"><span style="display:block">Ce</span></a></span>
</td>
<td title="Pr, Praseodymium" style="text-align:center; background-color:#9bff99; border:3px solid black; ;"><span class="nowrap"><a class="mw-selflink selflink"><span style="display:block">Pr</span></a></span>
</td>
<td title="Nd, Neodymium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Neodymium" title="Neodymium"><span style="display:block">Nd</span></a></span>
</td>
<td title="<span class=" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Promethium" title="Promethium"><span style="display:block"><span class="nowrap">Pm</span></span></a></span>
</td>
<td title="<span class=" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Samarium" title="Samarium"><span style="display:block"><span class="nowrap">Sm</span></span></a></span>
</td>
<td title="Eu, Europium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Europium" title="Europium"><span style="display:block">Eu</span></a></span>
</td>
<td title="Gd, Gadolinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Gadolinium" title="Gadolinium"><span style="display:block">Gd</span></a></span>
</td>
<td title="Tb, Terbium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Terbium" title="Terbium"><span style="display:block">Tb</span></a></span>
</td>
<td title="Dy, Dysprosium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Dysprosium" title="Dysprosium"><span style="display:block">Dy</span></a></span>
</td>
<td title="Ho, Holmium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Holmium" title="Holmium"><span style="display:block">Ho</span></a></span>
</td>
<td title="Er, Erbium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Erbium" title="Erbium"><span style="display:block">Er</span></a></span>
</td>
<td title="<span class=" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Thulium" title="Thulium"><span style="display:block"><span class="nowrap">Tm</span></span></a></span>
</td>
<td title="Yb, Ytterbium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Ytterbium" title="Ytterbium"><span style="display:block">Yb</span></a></span>
</td>
<td title="Lu, Lutetium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Lutetium" title="Lutetium"><span style="display:block">Lu</span></a></span>
</td>
<td title="Hf, Hafnium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Hafnium" title="Hafnium"><span style="display:block">Hf</span></a></span>
</td>
<td title="Ta, Tantalum" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Tantalum" title="Tantalum"><span style="display:block">Ta</span></a></span>
</td>
<td title="W, Tungsten" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Tungsten" title="Tungsten"><span style="display:block">W</span></a></span>
</td>
<td title="Re, Rhenium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Rhenium" title="Rhenium"><span style="display:block">Re</span></a></span>
</td>
<td title="Os, Osmium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Osmium" title="Osmium"><span style="display:block">Os</span></a></span>
</td>
<td title="Ir, Iridium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Iridium" title="Iridium"><span style="display:block">Ir</span></a></span>
</td>
<td title="Pt, Platinum" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Platinum" title="Platinum"><span style="display:block">Pt</span></a></span>
</td>
<td title="Au, Gold" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Gold" title="Gold"><span style="display:block">Au</span></a></span>
</td>
<td title="Hg, Mercury" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Mercury_(element)" title="Mercury (element)"><span style="display:block">Hg</span></a></span>
</td>
<td title="Tl, Thallium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Thallium" title="Thallium"><span style="display:block">Tl</span></a></span>
</td>
<td title="Pb, Lead" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Lead" title="Lead"><span style="display:block">Pb</span></a></span>
</td>
<td title="Bi, Bismuth" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Bismuth" title="Bismuth"><span style="display:block">Bi</span></a></span>
</td>
<td title="Po, Polonium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Polonium" title="Polonium"><span style="display:block">Po</span></a></span>
</td>
<td title="At, Astatine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Astatine" title="Astatine"><span style="display:block">At</span></a></span>
</td>
<td title="Rn, Radon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Radon" title="Radon"><span style="display:block">Rn</span></a></span>
</td></tr>
<tr>
<th scope="row" style="background:transparent; font-weight:normal;"><a href="/info/en/?search=Period_7_element" title="Period 7 element">7</a>
</th>
<td title="Fr, Francium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Francium" title="Francium"><span style="display:block">Fr</span></a></span>
</td>
<td title="Ra, Radium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Radium" title="Radium"><span style="display:block">Ra</span></a></span>
</td>
<td title="Ac, Actinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Actinium" title="Actinium"><span style="display:block">Ac</span></a></span>
</td>
<td title="Th, Thorium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Thorium" title="Thorium"><span style="display:block">Th</span></a></span>
</td>
<td title="Pa, Protactinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Protactinium" title="Protactinium"><span style="display:block">Pa</span></a></span>
</td>
<td title="U, Uranium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Uranium" title="Uranium"><span style="display:block">U</span></a></span>
</td>
<td title="Np, Neptunium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Neptunium" title="Neptunium"><span style="display:block">Np</span></a></span>
</td>
<td title="Pu, Plutonium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Plutonium" title="Plutonium"><span style="display:block">Pu</span></a></span>
</td>
<td title="<span class=" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Americium" title="Americium"><span style="display:block"><span class="nowrap">Am</span></span></a></span>
</td>
<td title="<span class=" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Curium" title="Curium"><span style="display:block"><span class="nowrap">Cm</span></span></a></span>
</td>
<td title="Bk, Berkelium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Berkelium" title="Berkelium"><span style="display:block">Bk</span></a></span>
</td>
<td title="Cf, Californium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Californium" title="Californium"><span style="display:block">Cf</span></a></span>
</td>
<td title="Es, Einsteinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Einsteinium" title="Einsteinium"><span style="display:block">Es</span></a></span>
</td>
<td title="<span class=" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Fermium" title="Fermium"><span style="display:block"><span class="nowrap">Fm</span></span></a></span>
</td>
<td title="Md, Mendelevium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Mendelevium" title="Mendelevium"><span style="display:block">Md</span></a></span>
</td>
<td title="No, Nobelium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Nobelium" title="Nobelium"><span style="display:block">No</span></a></span>
</td>
<td title="Lr, Lawrencium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Lawrencium" title="Lawrencium"><span style="display:block">Lr</span></a></span>
</td>
<td title="Rf, Rutherfordium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Rutherfordium" title="Rutherfordium"><span style="display:block">Rf</span></a></span>
</td>
<td title="Db, Dubnium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Dubnium" title="Dubnium"><span style="display:block">Db</span></a></span>
</td>
<td title="Sg, Seaborgium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Seaborgium" title="Seaborgium"><span style="display:block">Sg</span></a></span>
</td>
<td title="Bh, Bohrium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Bohrium" title="Bohrium"><span style="display:block">Bh</span></a></span>
</td>
<td title="Hs, Hassium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Hassium" title="Hassium"><span style="display:block">Hs</span></a></span>
</td>
<td title="Mt, Meitnerium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Meitnerium" title="Meitnerium"><span style="display:block">Mt</span></a></span>
</td>
<td title="Ds, Darmstadtium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Darmstadtium" title="Darmstadtium"><span style="display:block">Ds</span></a></span>
</td>
<td title="Rg, Roentgenium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Roentgenium" title="Roentgenium"><span style="display:block">Rg</span></a></span>
</td>
<td title="Cn, Copernicium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Copernicium" title="Copernicium"><span style="display:block">Cn</span></a></span>
</td>
<td title="Nh, Nihonium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Nihonium" title="Nihonium"><span style="display:block">Nh</span></a></span>
</td>
<td title="Fl, Flerovium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Flerovium" title="Flerovium"><span style="display:block">Fl</span></a></span>
</td>
<td title="Mc, Moscovium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Moscovium" title="Moscovium"><span style="display:block">Mc</span></a></span>
</td>
<td title="Lv, Livermorium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Livermorium" title="Livermorium"><span style="display:block">Lv</span></a></span>
</td>
<td title="Ts, Tennessine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Tennessine" title="Tennessine"><span style="display:block">Ts</span></a></span>
</td>
<td title="Og, Oganesson" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/info/en/?search=Oganesson" title="Oganesson"><span style="display:block">Og</span></a></span>
</td></tr></tbody></table>
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</td>
<td style="padding:0 1px; background:#99ccff;"><a href="/info/en/?search=D-block" class="mw-redirect" title="D-block">d-block</a>
</td>
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<ul><li><a href="/info/en/?search=Praseodymium(II)_iodide" class="mw-redirect" title="Praseodymium(II) iodide">PrI<sub>2</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_monoselenide" title="Praseodymium monoselenide">PrSe</a></li>
<li><a href="/info/en/?search=Praseodymium_pentaphosphide" title="Praseodymium pentaphosphide">PrP<sub>5</sub></a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pr(III)</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="/info/en/?search=Praseodymium(III)_nitrate" title="Praseodymium(III) nitrate">Pr(NO<sub>3</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_sulfate" title="Praseodymium(III) sulfate">Pr<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_selenate" title="Praseodymium(III) selenate">Pr<sub>2</sub>(SeO<sub>4</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_fluoride" title="Praseodymium(III) fluoride">PrF<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_chloride" title="Praseodymium(III) chloride">PrCl<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_bromide" title="Praseodymium(III) bromide">PrBr<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_iodide" title="Praseodymium(III) iodide">PrI<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_nitride" class="mw-redirect" title="Praseodymium nitride">PrN</a></li>
<li><a href="/info/en/?search=Praseodymium_phosphide" class="mw-redirect" title="Praseodymium phosphide">PrP</a></li>
<li><a href="/info/en/?search=Praseodymium_arsenide" title="Praseodymium arsenide">PrAs</a></li>
<li><a href="/info/en/?search=Praseodymium_antimonide" title="Praseodymium antimonide">PrSb</a></li>
<li><a href="/info/en/?search=Praseodymium_bismuthide" title="Praseodymium bismuthide">PrBi</a></li>
<li><a href="https://en.wikipedia.org/?title=Praseodymium_oxyiodide&action=edit&redlink=1" class="new" title="Praseodymium oxyiodide (page does not exist)">PrOI</a></li>
<li><a href="/info/en/?search=Praseodymium(III)_acetate" title="Praseodymium(III) acetate">Pr(CH<sub>3</sub>COO)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_hydroxide" title="Praseodymium(III) hydroxide">Pr(OH)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_oxide" title="Praseodymium(III) oxide">Pr<sub>2</sub>O<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_sulfide" title="Praseodymium(III) sulfide">Pr<sub>2</sub>S<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_perchlorate" class="mw-redirect" title="Praseodymium perchlorate">Pr(ClO<sub>4</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_bromate" title="Praseodymium bromate">Pr(BrO<sub>3</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_iodate" title="Praseodymium(III) iodate">Pr(IO<sub>3</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_molybdate" title="Praseodymium(III) molybdate">Pr<sub>2</sub>(MoO<sub>4</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(III)_phosphate" title="Praseodymium(III) phosphate">PrPO<sub>4</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_acetylacetonate" title="Praseodymium acetylacetonate">Pr(C<sub>5</sub>H<sub>7</sub>O<sub>2</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_arsenate" title="Praseodymium arsenate">PrAsO<sub>4</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_orthoscandate" title="Praseodymium orthoscandate">PrScO<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_oxalate" class="mw-redirect" title="Praseodymium oxalate">C<sub>6</sub>O<sub>12</sub>Pr<sub>2</sub></a></li></ul></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Organopraseodymium(III)_compounds" scope="row" class="navbox-group" style="width:1%"><a href="/info/en/?search=Organolanthanide_chemistry" title="Organolanthanide chemistry">Organopraseodymium(III) compounds</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">
<li><a href="/info/en/?search=Praseodymium(III)_carbonate" title="Praseodymium(III) carbonate">Pr<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub></a></li>
<li><a href="/info/en/?search=Praseodymium_oxalate" class="mw-redirect" title="Praseodymium oxalate">Pr<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub></a></li>
</div></td></tr></tbody></table><div>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pr(III,IV)</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="/info/en/?search=Praseodymium(III,IV)_oxide" title="Praseodymium(III,IV) oxide">Pr<sub>6</sub>O<sub>11</sub></a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pr(IV)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="/info/en/?search=Praseodymium(IV)_fluoride" title="Praseodymium(IV) fluoride">PrF<sub>4</sub></a></li>
<li><a href="/info/en/?search=Praseodymium(IV)_oxide" title="Praseodymium(IV) oxide">PrO<sub>2</sub></a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pr(V)</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="/info/en/?search=Praseodymium(V)_oxide_nitride" title="Praseodymium(V) oxide nitride">PrNO</a></li></ul>
</div></td></tr></tbody></table></div>
<div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1061467846"></div><div role="navigation" class="navbox authority-control" aria-label="Navbox" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/info/en/?search=Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q1386#identifiers" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="https://upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="https://upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><span class="uid"><a class="external text" href="https://d-nb.info/gnd/4175591-1">Germany</a></span></li>
<li><span class="uid"><a class="external text" href="https://olduli.nli.org.il/F/?func=find-b&local_base=NLX10&find_code=UID&request=987007531660105171">Israel</a></span></li>
<li><span class="uid"><a class="external text" href="https://id.loc.gov/authorities/sh85106095">United States</a></span></li></ul>
</div></td></tr></tbody></table></div></div>' |