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As mentioned on Wikipedia talk:Requests for mediation/Depleted uranium and related articles, there are now scans of new source articles in:
http://www.bovik.org/du/scans/
-- James S. 05:42, 23 February 2006 (UTC)
I moved the discussion of UO3 gas into comment temporarily until I can look into the literature. Anyway, gaseous UO3 seems to be a minor aspect of the basic chemistry of the material uranium trioxide, which is what readers will be seeking in this article. The next order of business might be to describe the solid state coordination environment of UO3 and its simple hydrates, as summarized in "Structural Inorganic Chem." -- Smokefoot 18:10, 24 February 2006 (UTC)
Hi Nrcprm2026 it looks like you are editing UO3 article e.g. by inserting "UO3 bond angles are about 90 and 180 degrees, with bond lengths between 1.2 and 2.2 Angstroms; the narrower uranium ion is in the central position." The phrasing is unusually non-chemical, and more specifically the bond angles and distances also seem unexpected. I was wondering if this is a joke or something?I was going to edit this silly phrase but I get the feeling that there's a joke going on here. -- Smokefoot 00:44, 25 February 2006 (UTC)
No joke; replacing. -- James S. 09:31, 17 March 2006 (UTC)
Why does Smokefoot claim DV8 2XL's edit? -- James S. 05:16, 25 February 2006 (UTC)
Hey Nrcprm2026: Sorry you got me there, I am not a wiki-expert - and am making only slow progress with the syntax - so I dont know what a sockpuppet is, but I figure it is not a compliment. Now that I have your attention, what is a "narrow atom" and where did you get the structural data on UO3, like the extraordinarily short U-O distance? I am a boring inorganic chemist who just wants to contribute data and mainly reactions in context of other oxides, chlorides, and sulfides. I had to pull student from UO3 work because I thought that the history of that article became too strange. -- Smokefoot 05:30, 25 February 2006 (UTC)
Given the good faith questions that this raises in a mediation of which I am a part, I think I'm going to ask for this question to be reviewed by an administrator with CheckUser privleges, although given the edit history it looks pretty obvious what happened here. What a tangled web we weave.... -- James S. 08:10, 25 February 2006 (UTC)
I suspect, James because it was right. Now, do the check user thing and apolgise to both of us. -- DV8 2XL 19:42, 25 February 2006 (UTC)
Hallelujah. And thanks for everything you've tried to do to bring reason and civility to this issue, Physchim62. Dr U 15:11, 26 February 2006 (UTC)
Some uranyl oxide gas is produced when uranium burns in air.
I removed the inappropriate references; the case is proven by Wilson (1961) quoting Ackermann (1960). -- James S. 19:57, 12 March 2006 (UTC)
Nothing that you have posted in the way of reference speaks to this gas to anyone except you James. Nothing. Please leave this article as is untill you do find proper citations, and establish that the do in fact support your views. -- DV8 2XL 14:29, 13 March 2006 (UTC)
Bei 1200 bis 1800 K (not 300 K) verdampft festes U3O8 in Gegenwart von [molekularen] Sauerstoff zu gasfoermigem, vermutlich monomerem UO3.
Gmelin Handbuch der anorganischen Chemiek_, 8th edition, volume U-C2 (1978), page 118,
B. Salbu, et al., in "Oxidation states of uranium in depleted uranium particles from Kuwait," Journal of Environmental Radioactivity, vol. 78, no. 2 (October 2004) pp. 125-135, found spectrographic evidence of hexavalent uranium ions and UO3 particles (no gas) in an enclosed pyrophoric uranium munitions burn.
R.L. Gilchrist, J.A. Glissmyer, and J. Mishima, "Characterization of Airborne Uranium from Test Firings of XM774 Ammunition," PNL-2944, Richland, WA: Battelle Pacific Northwest Laboratory, November 1979. The combustion products were described thusly, "About 75% of the airborne DU was U3O8, and 25% was UO2." NO UO3 http://www.gulflink.osd.mil/du_ii/du_ii_tabl1.htm http://www.gulflink.osd.mil/du_ii/du_ii_tabl2.htm No mention of "uranium trioxide" or "UO3" is made on either of those summary compilation pages.
The summary for M.A. Parkhurst, J.R. Johnson, J. Mishima, and J.L. Pierce, "Evaluation of DU Aerosol Data: Its Adequacy for Inhalation Modeling," PNL-10903, Richland, WA: Battelle Pacific Northwest Laboratory, December 1995, No mention is made of the uranium trioxide.
Mitsakou, et al., "Modeling the Dispersion of Depleted Uranium Aerosol," Health Physics, vol. 84, no. 4 (2003) pp. 538-544, and R.E.J. Mitchel and S. Sunder, "Depleted Uranium Dust from Fired Munitions: Physical, Chemical and Biological Properties," Health Physics, vol. 87, no. 1 (2004), pp. 57-67; neither find any form of hexavalent uranium at all.
I find no hint for gas at normal temperature in any of these articles! -- Stone 10:49, 14 March 2006 (UTC)
The above-cited literature neglects UO3 at room temperature. So where is the proof for UO3 at room temperature and normal pressure? Ackermann and Nakajima are no proof one is high temperature the other low pressure. Mass spectroscopy is done at very low pressure! -- Stone 16:50, 14 March 2006 (UTC)
With a melting point of 500°C there is no gas at 400°C during the synthesis!-- Stone 16:50, 14 March 2006 (UTC)
Normal methode for purification is chemical transport reaction. Ackermann writes it in his paper that he uses it do purify the U3O8 and to get crystals. There is tonns of literature on chemical transport reactions. ( Holleman Wieberg, Lehrbuch der Anorganischen Chemie 1985, for the Mond process)-- Stone 16:50, 14 March 2006 (UTC)
I was looking at WebElements UO3 page. Under melting point, it says decomposes to to U3O8 - does anyone know what temperature this happens at?
Following the link to the
U3O8 page, I find the m.p. is given as 1150 °C; 1300 °C decomposes to UO2. And
UO2's m.p. is given as 2827 °C. It would be nice to have this information stated simply in a section or in the infobox. I'm scared to touch this article, though, for all the heated debate I've seen on the talk page and elsewhere.
If this info is accurate, there should be a sequence of events like this:
UO3(s) → (at ?°C) → U3O8(s) → (at 1150°C) → U3O8(l) → (at 1300°C) → UO2(s) → (at 2827 °C) → UO2(l)
I'm finding this article a bit confusing to read. Can the basic chemistry (that all textbooks agree on!) be near the top of the article, leaving the row about UO3 gas for the bottom of the page. I know I'm only a student and I don't have seven PhD's like most of you who contribute to this article, but I'm sure many, if not most, people who look for uranium trioxide on Wikipedia aren't experts and would prefer the simple information first.
I found the following sections to be unsupported so I removed them:
-- James S. 23:28, 14 March 2006 (UTC)
Sometimes there's a section in this article saying UO3 cannot decompose to UO + O2 because UO is electrovalently impossible. However, in this reference from bovik.org, the very same page that gives the formula 1/3 U3O8(s) + 1/6 O2(g) → UO3(g) also says "small amount of UO(g), UO2(g)" - therefore, whatever electrovalence has to say on the issue, UO seems to exist. —Preceding unsigned comment added by Benjah-bmm27 ( talk • contribs)
Please try to keep from confusing the pressures of UO3(g) sublimation in near-vacuum for late-1950s spectrography used to derive thermodynamic formation data with UO3(g) formation from ionic plasma after combustion. The two are entirely different. For one thing, sublimation is a surface effect (and surface is proportional to the inverse of the cube of particle size -- and Ackerman et al. (1960) used micron-scale particles) while gas formation from ionic plasma is a dissolved solution reaction, with the maximum possible surface area in effect. The thermodynamic energies of formation for UO3(g), UO2(g) -- both negative net -- and UO(g) -- which is positive -- are shown in the OECD reference which Cadmium found. Thank you. -- James S. 17:11, 15 March 2006 (UTC)
Uranium is oxidized to Uranium trioxide and than sublimated to form Uranium trioxide gaseous. AAA kJ/mol
Uranium is evaporated and than oxidised in gas phase to Uranium trioxide gaseous. BBB kJ/mol
Uranium and oxygen form a plasma and while cooling oxidised in gas phase to Uranium trioxide gaseous. CCC kJ/mol
AAA=BBB=CCC
It does not matter which way to get to the Uranium trioxide gaseous all energies are the same. -- Stone 14:08, 16 March 2006 (UTC)
Ok! But the other numers are all the same and with this there is no UO3 in gas phase because the energy gained by condensation is high! -- Stone 20:45, 17 March 2006 (UTC)
The reaction from Uranium trioxide gaseous to Uranium trioxide solid is a simple sublimation reaction. DDD kJ/mol
The way this sublimation is going makes no difference for the energy. Energy for sublimation is DDD and for condensation is –DDD.
If the energy for sublimation is large the energy for condensation is also large too. The low vapour pressure at 2300K of 0.34 Pa indicates clearly that the energy for sublimation is high. With this high energy the energy for condensation is also high.
Statement: The energy for sublimation is high. (or not?)
This lead to fast condensation to the solid Uranium trioxide.
If there is a compound with a low vapour pressure or high energy for sublimation and forms a gas as a predominant species over a broad range of temperature and pressure this would harm hurt or kill the Born Haber Cycle and a perpetuum mobile would be in accessible in an easy way.
There is no chance that with 0.34 Pa at 2300K (or is this number also under discussion?) that there is more Uranium trioxide is in gas phase at lower temperature. Condensation reaction takes place at any particle in the atmosphere till equilibrium is reached. This equilibrium has to be on the side of Uranium trioxide not the gas phase. -- Stone 14:08, 16 March 2006 (UTC)
The reaction is somewhat different but the reaction which is important is the reaction back to the solid phase which is the same and hase the same energy. It is not important where you come from! -- Stone 11:53, 19 March 2006 (UTC)
Chemicla transport reactions of Chlorides Fluorides and oxides are often used for purification so: The mond process was used by Ackermann to purify the U3O8! So why is it not a chemical transport reaction which is closely related to the mond process? greizbirnbamholastauden -- Stone 10:26, 16 March 2006 (UTC)
Mond process is the only chemical transport reaction I found in the Wikipedia. Sublimation is a physical gas phase transport reaction. Where the solide has the same composition than the gas phase and the then forming gasphase.
Chemical transport reaction: the substance undergoes a chemical reaction to a other species and at a point with a different temperature the reversereaction takes place and the same substance as in the beginning is there.
For me reading the chemical transport reaction is what takes place in the reaction chamber discribed by Ackermann. And for not having a chemical transport reaction the link to the[[Mond process] is the best we have. -- Stone 18:45, 17 March 2006 (UTC)
This is an encyclopedic article on uranium trioxide. That, under laboratory conditions, or in the center of a flame some molecules with enough kinetic energy to be theoretically defined as a gas may exist for a moment is really not germane to a general treatment of this compound. Only one editor wishes to keep this discussion in this article to support a contention elsewhere on Wikipedia that this gas is a factor in human exposure to uranium. If it is to remain here then this sub topic must be given a full treatment detailing exactly and in no uncertain terms the physical conditions that this gas forms, it's relative volumes, and it's short lifespan; or the entire passage removed as non notable. -- DV8 2XL 15:15, 16 March 2006 (UTC)
UO3 vapor; Total inhalation exposure; Teratogenicity; Neurotoxicity; Carcinogenicity; and other questions from "Can the value of a human poison be known without knowledge of its long-term effects?" to "Does the oxygen gradient in a fire modify the effective surface area of burning particles by a scalar value?" ( history.) -- James S. 08:54, 17 March 2006 (UTC)
Reference needed for:
The uranium trioxide is shipped between processing facilities in the form of a UO3 gel. In the jargon of the uranium refining industry, the chemical solution containing the concentrated uranium trioxide is called "OK liquor". Upon heating, this material liberates ammonia, giving UO3
Reference needed for:
UO3 bond angles are about 90 and 180 degrees, with bond lengths between 1.5 and 2.2 Angstroms; the narrower uranium ion is in the central position.
Gaseous monomeric UO3 is produced by combustion of uranium metal in air from 2200-2800 Kelvin
Ackermann RJ, Thorn RJ, Alexander C, Tetenbaum M (1960). "Free Energies of Formation of Gaseous Uranium, Molybdenum, and Tungsten Trioxides". J Phys Chem. 64: 350–355.{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
THE REFERENCED ACKERMANN STARTS FROM U3O8 NOT URANIUM
Mouradian EM, Baker L jr (1963). "Burning Temperatures of Uranium and Zirconium in Air". Nucl Sci Engen. 15: 388–394. THERE IS NO STATEMENT OF UO3 IN THE ARTICLE --COMBINATION OF THE ARTICLES GIVES A GOOD SUGGESTION; BUT AN EXTRAPOLATION FROM 1000-1300°K FROM ACKERMANN TO 2200°-2800°C IN MOURADIN IS NOT ALLOWED IF OXYGEN LOSS IS POSSIBLE-SECOND POINT: THE PRESSURE OF 10 EXP -7 ATM AT 1300°C EXTRAPOLATION TO 300°K GIVES 10 EXP -53 ATM WHICH IS REALLY NOT MUCH
The production of UO3 gas vapor is "not infrequently ignored" (Gmelin vol. U-C1, p. 98). UO3(g) molecules condense. IF THE "not infrequently ignored"
UO3 WOULD BE A MAYOR POINT AS MAYOR PRODUCT IF URANIUM IS BURNING IN OXYGEN. IT WOULD BE MENTIONED IN THE PAPER:
Salbu B, Janssens K, Lind OC, Proost K, Gijsels L, Danesi PR (2005). "Oxidation states of uranium in depleted uranium particles from Kuwait". Journal of Environmental Radioactivity. 78: 125–135.{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
"Thus, environmental or health impact assessments for areas affected by DU munitions should take into account the presence of respiratory UO2, U3O8 and even UO3 particles, theircorresponding weathering rates and the subsequent mobilisation of U from oxidized DU particles." THE OTHER OXIDES ARE ALSO NOT VERY VOLATILE AND THEY ARE FOUND IN THE RESIDUE, So WHERE HAS AL THE UO3 GONE.
If you would stick to the respiratory UO3 particles everything would be OK. They disolve more readyly in the lung and have a bigger effect than the unsoluable U3O8 and UO2, but the gas phase is simply wrong.
Wilson WB (1961). "High-Pressure High-Temperature Investigation of the Uranium-Oxygen System". J Inorg Nuclear Chem. 19: 212–222. WILSON STATES: "U3O8 to UO3, are not included, since they are beyond the compositional range of the present investigation." WHY CITE HIM THEN.
Guido M, Balducci G (1991). "Identification and stability of U3O3U3O3 and U3O3 (g) gasous oxides molecules". J Phys Chem. 95: 5373–5376. GUIDO STATES THAT UO2 IS THE PREDOMINANT SPECIES IN THE MASS SPEC FOLLOWED BY UO THAN THE UO3: "corresponding to corrected ion intensities, in pA, of 1102, 20702, 285, 0.6,0.45, and 0.6 for the UO+, UO2+, UO3+, U2O2+, U2O3+, and U2O4+ ions, respectively" WHY IS THAN UO2 THE MAIN COMPOUND IN THE GASPHASE?
Individual UO3 gas vapor molecules will not decompose below the burning temperature of uranium in air, because uranium monoxide requires additional energy to form, as does the release of O2 by a single UO3 molecule. (Hoekstra and Siegel 1958; Wanner and Forest (2004) p. 98.)
Other literature:
Nakajima K Arai Y (2001). J Nuclear Mater. 294: 250–255. {{
cite journal}}
: Missing or empty |title=
(
help); Text "title Mass-spectrometric investigation of) UO3 (g)" ignored (
help)
Chatillion C, Defoort F, Froment K (2005). "Mass spectrometric critical assessment of thermodynamic data for UO3 (g)". J Phys Chem Solid. 66: 379–382.{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
THE NITROGEN COMPOUNDS SHOULD GO TO THEIR OWN PAGE, AS THE URANIUM TRIOXIDE IS NOT THE MAIN PRODUCT IN AIRIAL COMBUSTION OF URANIUM. IT SHOUL GO TO THE U3O8 WHICH IS THE MAIN PRODUCT OF COMPUSTION.
Uranium-nitrogen salts UNx, where x usually is one, form above 800 degrees Celsius. S. Cotton (1991) Lanthanides and Actinides (New York: Oxford University Press) also writes, on page 127: "Aerial oxidation of any uranium compound eventually results in the formation of a uranyl compound."--
Stone
20:00, 20 March 2006 (UTC)
Than but it on the page for Du or somewhat else but this page is about UO3 not the combustion products of Uranium.-- Stone 08:14, 21 March 2006 (UTC)
Please leave these calculations alone, if you want to comment please do so in the sub section marked comments. I am making a point of doing the calculations in plain sight.
For the conversion of uranium metal to the monoatomic gas at STP, DeltaH = 533.0 +- 8.0 KJ mol-1
If we assume the reaction 2U + 3O2 to make 2UO3 then we can assume that the oxygen atoms (arrnaged in molecules are already in the gas phase. So no heat is required to form the oxygen gas.
Using Hess's Law, as the Delta H of formation of UO3 gas (from metallic U) is listed at -799.2 KJ mol-1, we can assume that the energy for the conversion of the monoatomic gas to the UO3 gas is 1332.2 KJ mol-1. This has allowed us to get to the point where we can draw a simple Born Haber cycle. This is rather mundane.
The next step is more interesting, assume that a uranium fire occurs in air (20% O2 and 80% N2). For the purposes of the calculation assume that the uranium oxide product is in the form of a gas.
2U + 3 O2 + 12 N2 --> 2 UO3 + 12 N2
We can expect that the reaction will generate 799.2 KJ mol-1
If we assume that no heat is transfered ( adiabatic) system the it is possible to eastimate the flame temperture. I hope to goodness that this does not start a flame war, dire pun
The molar heat capacity of UO3 gas listed in my fav. source is 64.5 (plus minus 2) J K-1 mol-1
[2] states that the molar heat capacity of nitrogen is 20.8 J K-1 mol-1
So the heat capacity of 2 UO3 + 12 N2 will be (2 x 64.5) + (12 x 20.8) J K-1 mol-1
Which is 189.3 J K-1 mol-1 for each mole of uranium which burns. Call this Cx
Each mole of uranium which burns to make the gas, will give out 799.2 KJ (Delta H)
T = 298 K + (Delta H/Cx) = 298 + 4222 K = 4520 K
This is going to be very hot, and could cause uranium oxide gas to form for a moment. As the mixture is cooled by mixing with more air, the uranium oxide will then condense. The calculation which I have done is for a rare case of uranium being vapourised and then oxidised, this would happen in reactive spluttering where in an argon/oxygen gas at low preasure uranium atoms are spalled off of a surface by plasma discharge. So I think that it is reasonable to assume that uranium trioxide gas can be formed (for a moment) by burning uranium under a set of idealised conditions, but I expect that it will rapidly condense onto a surface.
Anyone who wants to is welcome to check my maths:) Cadmium
Flame temperature data. -- James S. 20:14, 17 March 2006 (UTC)
Willson has done no research on UO3 he only quotes the ackeman paper nothing more. -- Stone 08:53, 23 March 2006 (UTC)
Lets start wit the equation it self: can be found in [3]
log p= (((1.821 ± 0.075)· 104)/T) + 6.84 ± 0.58 log p= (((1.856 ± 0.016)· 104)/T) + 6.928 ± 0.103
I choose the first equation because it gives the higher pressure for UO3 gas.
log p= (((1.821 ± 0.075)· 104)/T) + 6.84 ± 0.58
Lets state 300K as the temperature (26°C or so)
putting in the numbers gives:
log p = -53.86
put both sides in the power over ten (native speaker needed)
p = 10-53.86 atm
p = 1.38 · 10-54 atm
convert from atm to Pa (1 atm = 101325 Pa)
p = 1.3985 · 10-49 Pa (N/m2)
Assuming that the laws of ideal gas are good for this problem
(which they are not, because the the condensation and the interaction between the molecules give even lower pressure for real gas at lower temperature than expected by the ideal gas euqaution)
p V= n R T
n = (p · V) / (R · T)
n =(1.3985 · 10-49 N/m2 · 1 m3)/ (8.314472 J · K-1 · mol-1 · 300 K)
n = 5.57 · 10-53 mol
so this is the number of mol per cubic meter of uranium trioxide.
1 mol = 6.023 · 1023 particles
So to get the number of particles in one cubic meter simpl multipie the numbers.
6.023 · 1023 5.57 · 10-53 = 3.35 · 10-29 particle per m3
Other way to point this numer is you need 2.98 · 1028 m3 to find on single atom of UO3.
Volume of earth 1.0832×1012 km3 = 1.0832×1021 m3 so even if the whole earth would be atmosphere there would be no molecule founnd in it. 600 times earth volume and you find your UO3.
Where is your calculation on this topic?
-- Stone 08:53, 23 March 2006 (UTC)
The pressure is absulutly independent on the surface! It is only the equilibrium reached faster if the surface is higher! A bound of sugar dissolves in a litre of water faster if you grind it, but the amount of sugar in the water will be in the end the same. Mass action there is no surface in this law for solution and condensation. -- Stone 11:46, 23 March 2006 (UTC)
Under the above theory of sublimation-as-combustion, the nearly exclusive combustion product would be uranium(0) metal. Sorry, that is incorrect. Please try again. -- 171.64.133.83 19:08, 23 March 2006 (UTC)
So is there any shred of a doubt in anyone's mind that UO3(g) is NOT a factor in uranium combustion in open air? Can we put this to rest, and remove its mention from the article now? -- DV8 2XL 19:11, 23 March 2006 (UTC)
The amount of dust makes a huge difference, but doesn't affect the solubility very much. There are probably some in your lungs right now. I am having trouble figuring out exactly how many because some of the statistics involve catastrophic distributions (lognornals on integers with deviations or variances greater than their means or modes) and I do not know how to transit confidence interval bounds through them yet. -- James S. 20:39, 24 March 2006 (UTC)
It's not a personal attack to point out that someone is wrong, or confused. You are in the wrong here James, plain and simple, you have been told over and over again by everyone that has looked at this subject. We have all taken great pains to look over your source material and point out where you have gone wrong in your reasoning and understanding of the fundamentals, yet you still claim that your thesis is the right one and that it is properly sourced when it has been clearly demonstrated erroneous. Your are not a scientist, not by station, not by knowledge, not by conduct. You are now simply just another pathetic crank. -- DV8 2XL 22:51, 24 March 2006 (UTC)
First I don't believe your are sorry at all for driving me off - in fact I believe that you have entered this argument at this late date to try and repeat it.
I have called James out for what he is; he has shown absolutely no understanding of what many people have gone to the trouble to show him by calculation, and more telling he has not provided counter arguments using calculation himself, nor are you. He is obstreperously holding on to a position in the face of a monumental amount of proof that he is wrong. Because like you he cares nothing of science, truth or reason beyond the needs of a political agenda.
You also know absolutely nothing about the science or you would be able to follow the arguments that have been posted above. What you are talking about has absolutely nothing to do with the issues here at all since we are discussing the formation of one species, not the distribution of combustion products. And your arguments and examples are even more ridiculous than his -- DV8 2XL 05:10, 25 March 2006 (UTC)
DV82XL, thanks for the references (on my talk page) to prior history. Again, I'm a little puzzled what is going on here. In the past there seems to have been a strong argument over whether depleted uranium is a hazard, and there was much spirited debunking! On this page, that debate seems to have taken the form of an argument over whether uranium trioxide gas is produced by combustion of depleted uranium in air. That notion (that uranium trioxide gas is a final combustion product) seems to have been debunked rather thoroughly.
But I do not see anything that indicates UO3 is not produced at all by combustion of metallic uranium - clearly that will take a trip to the library to check some of the references in the debate.
Meanwhile, granting (for the sake of argument only) that UO3 might actually be produced by combustion (albeit perhaps in solid form as a kind of soot, or perhaps as a low-quantity side product compared to the full oxide), I don't see anything else in the article that seems out in left field. Is that the only thing you're currently concerned about in this particular article (never mind what went on over depleted uranium)?
Cheers, zowie 14:55, 25 March 2006 (UTC)
UO3 Gas. My personal conclusion.
Simple way to pu it: If water vapor is produced by a fire or other combustion the condensation rate and temperature is the same as if you produce the vapor by subliamtion or boiling. The Born haber cycle states this and makes nothing other possible.-- Stone 06:35, 27 March 2006 (UTC)
To the lamp black argumentation! You do exact the same like James! The lamp black is carbon produced by sublimation and part oxidation of organic materials. This is not C (gas). C gas is not stable in any conditions in air. So claiming that C gas is in the air for weeks is simply false! But you can do it as long its not in the carbon page. The lamp black you get from Borneo or from your oil lamp is graphit particles nothing more and nothing less. Particles can travel the world for years nobody will deny the fact and your obvious was never denied, but: THERE ARE NO GAS MOLECULES AROUND! The condensation takes place at temperatures where the equilibrium is reached fast and all the UO3 condenses and it forms small particles which can fly around similar to the gas molecules, but they are no gas and will never be.-- Stone 06:46, 27 March 2006 (UTC)
TO James. Where is the literature profe for the 5-6 Angström particles and their non condensation you claim earlier!-- Stone 06:46, 27 March 2006 (UTC)
Introduction
At the moment, the introduction stands as:
I was reading
Greenwood & Earnshaw (p. 1268) - here is their introduction to uranium trioxide:
Can we put in the fact that it is γ-UO3 that is obtained by heating uranyl nitrate at 400°C? -- Ben 13:11, 25 March 2006 (UTC).
I think we should move the words toxic and teratogenic to a subsection, because it's confusing to have physical and chemical properties listed in between the effects of UO3 on humans. To those of you who are thinking 'but UO3 is so toxic and teratogenic, we must make this clear right at the start of the article', I would ask you to take a look at isotretinoin. I found this from the article on teratogenesis - where it lists isotretinoin as a very strong teratogen. Even though its teratogenicity is very important, it is not discussed in the introduction in its article, but in a subsection further down.
I think this layout would help make the UO3 article more NPOV, as it would have the same emphasis on tetatogenicity as other articles. I am refraining from making this change immediately because of the great deal of dispute that exists surrounding this article. -- Ben 13:11, 25 March 2006 (UTC).
Structure
I've added a PNG of a UO3 molecule. I'm not sure if it is right. I know that UO3 is mostly encountered as a solid and as such has a crystal structure not represented by my diagram. I'll see if I can make a model of that too. I'm having trouble finding details of the structure of solid UO3 - there are seven forms apparently. If anyone can send me a pdb, mol, xyz or other file that iMol can read of the crystal structure of UO3, I'll happily make a PNG of this and upload it here.
Sorry for the long comment. I'm hoping for a happy ending to the wars on this article! -- Ben 13:11, 25 March 2006 (UTC).
Acta Cryst. (1963). 16, 993 The Crystal Structure of γ-UOs BY R. ENGIVKANN AND P. I~. DE WOLFF
Acta Cryst. (1966). 20, 292 The Crystal Structure of High-Pressure UO3* BY S. SIEGEL, H. HOEKSTRA AND E. SHERRY Acta Cryst. (1966). 21, 589 The Structure of β-UO3* BY P. C. DEBETS -- Stone 06:55, 27 March 2006 (UTC) UO3 vs. O3U
I put back in the NIST reference that was kindly added earlier, as NIST is widely recognized as an authoritative source. If they refer to the molecule as O3U then it is fair to say that at least a significant part of the scientific establishment calls it that. zowie 16:28, 26 March 2006 (UTC)
Where is the reference for the structure? This looks not very good for me! Hybridisation and the lone-pairs should also be shown, to get a picture if this structure could be right. Gaspahse spectroscopy for structural purpose was in no paper I found on my search for uraniumoxide gas. Even the the MS-spectroscopy papers do not state any structural data. -- Stone 08:03, 27 March 2006 (UTC)
The structure from Gmelin of the molecular UO3 is from deep temperature matrix experiments. UO3 is incorporated of a solid argon matrix which is inreactive against nearly everything at low temperatures. The Raman and IR spectroscopy date suggest that the linear UO22+ with a O2- on the side which gives T-shaped molecule. The trigonal planar (D3d) structure was also proposed but only favoured by calculations. The T-shape is only estimated by the symmetry of the vibrations shown in Raman and IR. (Comment for James: Raman is no MS spectroscopy, it is comparable to IR spectroscopy) The deep temperature argon matrix experiments are the state of the art experiment for instable molecules to be detected. In the matrix the molecules can not react with each other because they are separated by inreactive noble gas molecules und the necessary activation energy is not available at deep temperatures. (kinetically and thermodynamically hindered reaction conditions) The concentration of molecules can be high, because of that Raman and IR are able to detect them.
X-ray crystal structure is only possible for the solid and shows for gamma UO3 two types of uranium atoms the hexa (octaedric) coordinated in. The structure can described as UO22+ UO42-. In beta UO3 three types of uranium atoms are present. Two forming Uranyl with four oxygens in bigger distance. One with a octaedric surrounding and two with a octaedric surrounding connected over one oxygen. Which gives a 2(UO22+) UO42- U3O72- as a good suggestion.
Ackermann: These observations suggest the possibility that UO3 is the principal species in equilibrium with U3O8 under the experimental conditions. This is weak not a clear statement, at best.
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 | Archive 4 |
As mentioned on Wikipedia talk:Requests for mediation/Depleted uranium and related articles, there are now scans of new source articles in:
http://www.bovik.org/du/scans/
-- James S. 05:42, 23 February 2006 (UTC)
I moved the discussion of UO3 gas into comment temporarily until I can look into the literature. Anyway, gaseous UO3 seems to be a minor aspect of the basic chemistry of the material uranium trioxide, which is what readers will be seeking in this article. The next order of business might be to describe the solid state coordination environment of UO3 and its simple hydrates, as summarized in "Structural Inorganic Chem." -- Smokefoot 18:10, 24 February 2006 (UTC)
Hi Nrcprm2026 it looks like you are editing UO3 article e.g. by inserting "UO3 bond angles are about 90 and 180 degrees, with bond lengths between 1.2 and 2.2 Angstroms; the narrower uranium ion is in the central position." The phrasing is unusually non-chemical, and more specifically the bond angles and distances also seem unexpected. I was wondering if this is a joke or something?I was going to edit this silly phrase but I get the feeling that there's a joke going on here. -- Smokefoot 00:44, 25 February 2006 (UTC)
No joke; replacing. -- James S. 09:31, 17 March 2006 (UTC)
Why does Smokefoot claim DV8 2XL's edit? -- James S. 05:16, 25 February 2006 (UTC)
Hey Nrcprm2026: Sorry you got me there, I am not a wiki-expert - and am making only slow progress with the syntax - so I dont know what a sockpuppet is, but I figure it is not a compliment. Now that I have your attention, what is a "narrow atom" and where did you get the structural data on UO3, like the extraordinarily short U-O distance? I am a boring inorganic chemist who just wants to contribute data and mainly reactions in context of other oxides, chlorides, and sulfides. I had to pull student from UO3 work because I thought that the history of that article became too strange. -- Smokefoot 05:30, 25 February 2006 (UTC)
Given the good faith questions that this raises in a mediation of which I am a part, I think I'm going to ask for this question to be reviewed by an administrator with CheckUser privleges, although given the edit history it looks pretty obvious what happened here. What a tangled web we weave.... -- James S. 08:10, 25 February 2006 (UTC)
I suspect, James because it was right. Now, do the check user thing and apolgise to both of us. -- DV8 2XL 19:42, 25 February 2006 (UTC)
Hallelujah. And thanks for everything you've tried to do to bring reason and civility to this issue, Physchim62. Dr U 15:11, 26 February 2006 (UTC)
Some uranyl oxide gas is produced when uranium burns in air.
I removed the inappropriate references; the case is proven by Wilson (1961) quoting Ackermann (1960). -- James S. 19:57, 12 March 2006 (UTC)
Nothing that you have posted in the way of reference speaks to this gas to anyone except you James. Nothing. Please leave this article as is untill you do find proper citations, and establish that the do in fact support your views. -- DV8 2XL 14:29, 13 March 2006 (UTC)
Bei 1200 bis 1800 K (not 300 K) verdampft festes U3O8 in Gegenwart von [molekularen] Sauerstoff zu gasfoermigem, vermutlich monomerem UO3.
Gmelin Handbuch der anorganischen Chemiek_, 8th edition, volume U-C2 (1978), page 118,
B. Salbu, et al., in "Oxidation states of uranium in depleted uranium particles from Kuwait," Journal of Environmental Radioactivity, vol. 78, no. 2 (October 2004) pp. 125-135, found spectrographic evidence of hexavalent uranium ions and UO3 particles (no gas) in an enclosed pyrophoric uranium munitions burn.
R.L. Gilchrist, J.A. Glissmyer, and J. Mishima, "Characterization of Airborne Uranium from Test Firings of XM774 Ammunition," PNL-2944, Richland, WA: Battelle Pacific Northwest Laboratory, November 1979. The combustion products were described thusly, "About 75% of the airborne DU was U3O8, and 25% was UO2." NO UO3 http://www.gulflink.osd.mil/du_ii/du_ii_tabl1.htm http://www.gulflink.osd.mil/du_ii/du_ii_tabl2.htm No mention of "uranium trioxide" or "UO3" is made on either of those summary compilation pages.
The summary for M.A. Parkhurst, J.R. Johnson, J. Mishima, and J.L. Pierce, "Evaluation of DU Aerosol Data: Its Adequacy for Inhalation Modeling," PNL-10903, Richland, WA: Battelle Pacific Northwest Laboratory, December 1995, No mention is made of the uranium trioxide.
Mitsakou, et al., "Modeling the Dispersion of Depleted Uranium Aerosol," Health Physics, vol. 84, no. 4 (2003) pp. 538-544, and R.E.J. Mitchel and S. Sunder, "Depleted Uranium Dust from Fired Munitions: Physical, Chemical and Biological Properties," Health Physics, vol. 87, no. 1 (2004), pp. 57-67; neither find any form of hexavalent uranium at all.
I find no hint for gas at normal temperature in any of these articles! -- Stone 10:49, 14 March 2006 (UTC)
The above-cited literature neglects UO3 at room temperature. So where is the proof for UO3 at room temperature and normal pressure? Ackermann and Nakajima are no proof one is high temperature the other low pressure. Mass spectroscopy is done at very low pressure! -- Stone 16:50, 14 March 2006 (UTC)
With a melting point of 500°C there is no gas at 400°C during the synthesis!-- Stone 16:50, 14 March 2006 (UTC)
Normal methode for purification is chemical transport reaction. Ackermann writes it in his paper that he uses it do purify the U3O8 and to get crystals. There is tonns of literature on chemical transport reactions. ( Holleman Wieberg, Lehrbuch der Anorganischen Chemie 1985, for the Mond process)-- Stone 16:50, 14 March 2006 (UTC)
I was looking at WebElements UO3 page. Under melting point, it says decomposes to to U3O8 - does anyone know what temperature this happens at?
Following the link to the
U3O8 page, I find the m.p. is given as 1150 °C; 1300 °C decomposes to UO2. And
UO2's m.p. is given as 2827 °C. It would be nice to have this information stated simply in a section or in the infobox. I'm scared to touch this article, though, for all the heated debate I've seen on the talk page and elsewhere.
If this info is accurate, there should be a sequence of events like this:
UO3(s) → (at ?°C) → U3O8(s) → (at 1150°C) → U3O8(l) → (at 1300°C) → UO2(s) → (at 2827 °C) → UO2(l)
I'm finding this article a bit confusing to read. Can the basic chemistry (that all textbooks agree on!) be near the top of the article, leaving the row about UO3 gas for the bottom of the page. I know I'm only a student and I don't have seven PhD's like most of you who contribute to this article, but I'm sure many, if not most, people who look for uranium trioxide on Wikipedia aren't experts and would prefer the simple information first.
I found the following sections to be unsupported so I removed them:
-- James S. 23:28, 14 March 2006 (UTC)
Sometimes there's a section in this article saying UO3 cannot decompose to UO + O2 because UO is electrovalently impossible. However, in this reference from bovik.org, the very same page that gives the formula 1/3 U3O8(s) + 1/6 O2(g) → UO3(g) also says "small amount of UO(g), UO2(g)" - therefore, whatever electrovalence has to say on the issue, UO seems to exist. —Preceding unsigned comment added by Benjah-bmm27 ( talk • contribs)
Please try to keep from confusing the pressures of UO3(g) sublimation in near-vacuum for late-1950s spectrography used to derive thermodynamic formation data with UO3(g) formation from ionic plasma after combustion. The two are entirely different. For one thing, sublimation is a surface effect (and surface is proportional to the inverse of the cube of particle size -- and Ackerman et al. (1960) used micron-scale particles) while gas formation from ionic plasma is a dissolved solution reaction, with the maximum possible surface area in effect. The thermodynamic energies of formation for UO3(g), UO2(g) -- both negative net -- and UO(g) -- which is positive -- are shown in the OECD reference which Cadmium found. Thank you. -- James S. 17:11, 15 March 2006 (UTC)
Uranium is oxidized to Uranium trioxide and than sublimated to form Uranium trioxide gaseous. AAA kJ/mol
Uranium is evaporated and than oxidised in gas phase to Uranium trioxide gaseous. BBB kJ/mol
Uranium and oxygen form a plasma and while cooling oxidised in gas phase to Uranium trioxide gaseous. CCC kJ/mol
AAA=BBB=CCC
It does not matter which way to get to the Uranium trioxide gaseous all energies are the same. -- Stone 14:08, 16 March 2006 (UTC)
Ok! But the other numers are all the same and with this there is no UO3 in gas phase because the energy gained by condensation is high! -- Stone 20:45, 17 March 2006 (UTC)
The reaction from Uranium trioxide gaseous to Uranium trioxide solid is a simple sublimation reaction. DDD kJ/mol
The way this sublimation is going makes no difference for the energy. Energy for sublimation is DDD and for condensation is –DDD.
If the energy for sublimation is large the energy for condensation is also large too. The low vapour pressure at 2300K of 0.34 Pa indicates clearly that the energy for sublimation is high. With this high energy the energy for condensation is also high.
Statement: The energy for sublimation is high. (or not?)
This lead to fast condensation to the solid Uranium trioxide.
If there is a compound with a low vapour pressure or high energy for sublimation and forms a gas as a predominant species over a broad range of temperature and pressure this would harm hurt or kill the Born Haber Cycle and a perpetuum mobile would be in accessible in an easy way.
There is no chance that with 0.34 Pa at 2300K (or is this number also under discussion?) that there is more Uranium trioxide is in gas phase at lower temperature. Condensation reaction takes place at any particle in the atmosphere till equilibrium is reached. This equilibrium has to be on the side of Uranium trioxide not the gas phase. -- Stone 14:08, 16 March 2006 (UTC)
The reaction is somewhat different but the reaction which is important is the reaction back to the solid phase which is the same and hase the same energy. It is not important where you come from! -- Stone 11:53, 19 March 2006 (UTC)
Chemicla transport reactions of Chlorides Fluorides and oxides are often used for purification so: The mond process was used by Ackermann to purify the U3O8! So why is it not a chemical transport reaction which is closely related to the mond process? greizbirnbamholastauden -- Stone 10:26, 16 March 2006 (UTC)
Mond process is the only chemical transport reaction I found in the Wikipedia. Sublimation is a physical gas phase transport reaction. Where the solide has the same composition than the gas phase and the then forming gasphase.
Chemical transport reaction: the substance undergoes a chemical reaction to a other species and at a point with a different temperature the reversereaction takes place and the same substance as in the beginning is there.
For me reading the chemical transport reaction is what takes place in the reaction chamber discribed by Ackermann. And for not having a chemical transport reaction the link to the[[Mond process] is the best we have. -- Stone 18:45, 17 March 2006 (UTC)
This is an encyclopedic article on uranium trioxide. That, under laboratory conditions, or in the center of a flame some molecules with enough kinetic energy to be theoretically defined as a gas may exist for a moment is really not germane to a general treatment of this compound. Only one editor wishes to keep this discussion in this article to support a contention elsewhere on Wikipedia that this gas is a factor in human exposure to uranium. If it is to remain here then this sub topic must be given a full treatment detailing exactly and in no uncertain terms the physical conditions that this gas forms, it's relative volumes, and it's short lifespan; or the entire passage removed as non notable. -- DV8 2XL 15:15, 16 March 2006 (UTC)
UO3 vapor; Total inhalation exposure; Teratogenicity; Neurotoxicity; Carcinogenicity; and other questions from "Can the value of a human poison be known without knowledge of its long-term effects?" to "Does the oxygen gradient in a fire modify the effective surface area of burning particles by a scalar value?" ( history.) -- James S. 08:54, 17 March 2006 (UTC)
Reference needed for:
The uranium trioxide is shipped between processing facilities in the form of a UO3 gel. In the jargon of the uranium refining industry, the chemical solution containing the concentrated uranium trioxide is called "OK liquor". Upon heating, this material liberates ammonia, giving UO3
Reference needed for:
UO3 bond angles are about 90 and 180 degrees, with bond lengths between 1.5 and 2.2 Angstroms; the narrower uranium ion is in the central position.
Gaseous monomeric UO3 is produced by combustion of uranium metal in air from 2200-2800 Kelvin
Ackermann RJ, Thorn RJ, Alexander C, Tetenbaum M (1960). "Free Energies of Formation of Gaseous Uranium, Molybdenum, and Tungsten Trioxides". J Phys Chem. 64: 350–355.{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
THE REFERENCED ACKERMANN STARTS FROM U3O8 NOT URANIUM
Mouradian EM, Baker L jr (1963). "Burning Temperatures of Uranium and Zirconium in Air". Nucl Sci Engen. 15: 388–394. THERE IS NO STATEMENT OF UO3 IN THE ARTICLE --COMBINATION OF THE ARTICLES GIVES A GOOD SUGGESTION; BUT AN EXTRAPOLATION FROM 1000-1300°K FROM ACKERMANN TO 2200°-2800°C IN MOURADIN IS NOT ALLOWED IF OXYGEN LOSS IS POSSIBLE-SECOND POINT: THE PRESSURE OF 10 EXP -7 ATM AT 1300°C EXTRAPOLATION TO 300°K GIVES 10 EXP -53 ATM WHICH IS REALLY NOT MUCH
The production of UO3 gas vapor is "not infrequently ignored" (Gmelin vol. U-C1, p. 98). UO3(g) molecules condense. IF THE "not infrequently ignored"
UO3 WOULD BE A MAYOR POINT AS MAYOR PRODUCT IF URANIUM IS BURNING IN OXYGEN. IT WOULD BE MENTIONED IN THE PAPER:
Salbu B, Janssens K, Lind OC, Proost K, Gijsels L, Danesi PR (2005). "Oxidation states of uranium in depleted uranium particles from Kuwait". Journal of Environmental Radioactivity. 78: 125–135.{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
"Thus, environmental or health impact assessments for areas affected by DU munitions should take into account the presence of respiratory UO2, U3O8 and even UO3 particles, theircorresponding weathering rates and the subsequent mobilisation of U from oxidized DU particles." THE OTHER OXIDES ARE ALSO NOT VERY VOLATILE AND THEY ARE FOUND IN THE RESIDUE, So WHERE HAS AL THE UO3 GONE.
If you would stick to the respiratory UO3 particles everything would be OK. They disolve more readyly in the lung and have a bigger effect than the unsoluable U3O8 and UO2, but the gas phase is simply wrong.
Wilson WB (1961). "High-Pressure High-Temperature Investigation of the Uranium-Oxygen System". J Inorg Nuclear Chem. 19: 212–222. WILSON STATES: "U3O8 to UO3, are not included, since they are beyond the compositional range of the present investigation." WHY CITE HIM THEN.
Guido M, Balducci G (1991). "Identification and stability of U3O3U3O3 and U3O3 (g) gasous oxides molecules". J Phys Chem. 95: 5373–5376. GUIDO STATES THAT UO2 IS THE PREDOMINANT SPECIES IN THE MASS SPEC FOLLOWED BY UO THAN THE UO3: "corresponding to corrected ion intensities, in pA, of 1102, 20702, 285, 0.6,0.45, and 0.6 for the UO+, UO2+, UO3+, U2O2+, U2O3+, and U2O4+ ions, respectively" WHY IS THAN UO2 THE MAIN COMPOUND IN THE GASPHASE?
Individual UO3 gas vapor molecules will not decompose below the burning temperature of uranium in air, because uranium monoxide requires additional energy to form, as does the release of O2 by a single UO3 molecule. (Hoekstra and Siegel 1958; Wanner and Forest (2004) p. 98.)
Other literature:
Nakajima K Arai Y (2001). J Nuclear Mater. 294: 250–255. {{
cite journal}}
: Missing or empty |title=
(
help); Text "title Mass-spectrometric investigation of) UO3 (g)" ignored (
help)
Chatillion C, Defoort F, Froment K (2005). "Mass spectrometric critical assessment of thermodynamic data for UO3 (g)". J Phys Chem Solid. 66: 379–382.{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
THE NITROGEN COMPOUNDS SHOULD GO TO THEIR OWN PAGE, AS THE URANIUM TRIOXIDE IS NOT THE MAIN PRODUCT IN AIRIAL COMBUSTION OF URANIUM. IT SHOUL GO TO THE U3O8 WHICH IS THE MAIN PRODUCT OF COMPUSTION.
Uranium-nitrogen salts UNx, where x usually is one, form above 800 degrees Celsius. S. Cotton (1991) Lanthanides and Actinides (New York: Oxford University Press) also writes, on page 127: "Aerial oxidation of any uranium compound eventually results in the formation of a uranyl compound."--
Stone
20:00, 20 March 2006 (UTC)
Than but it on the page for Du or somewhat else but this page is about UO3 not the combustion products of Uranium.-- Stone 08:14, 21 March 2006 (UTC)
Please leave these calculations alone, if you want to comment please do so in the sub section marked comments. I am making a point of doing the calculations in plain sight.
For the conversion of uranium metal to the monoatomic gas at STP, DeltaH = 533.0 +- 8.0 KJ mol-1
If we assume the reaction 2U + 3O2 to make 2UO3 then we can assume that the oxygen atoms (arrnaged in molecules are already in the gas phase. So no heat is required to form the oxygen gas.
Using Hess's Law, as the Delta H of formation of UO3 gas (from metallic U) is listed at -799.2 KJ mol-1, we can assume that the energy for the conversion of the monoatomic gas to the UO3 gas is 1332.2 KJ mol-1. This has allowed us to get to the point where we can draw a simple Born Haber cycle. This is rather mundane.
The next step is more interesting, assume that a uranium fire occurs in air (20% O2 and 80% N2). For the purposes of the calculation assume that the uranium oxide product is in the form of a gas.
2U + 3 O2 + 12 N2 --> 2 UO3 + 12 N2
We can expect that the reaction will generate 799.2 KJ mol-1
If we assume that no heat is transfered ( adiabatic) system the it is possible to eastimate the flame temperture. I hope to goodness that this does not start a flame war, dire pun
The molar heat capacity of UO3 gas listed in my fav. source is 64.5 (plus minus 2) J K-1 mol-1
[2] states that the molar heat capacity of nitrogen is 20.8 J K-1 mol-1
So the heat capacity of 2 UO3 + 12 N2 will be (2 x 64.5) + (12 x 20.8) J K-1 mol-1
Which is 189.3 J K-1 mol-1 for each mole of uranium which burns. Call this Cx
Each mole of uranium which burns to make the gas, will give out 799.2 KJ (Delta H)
T = 298 K + (Delta H/Cx) = 298 + 4222 K = 4520 K
This is going to be very hot, and could cause uranium oxide gas to form for a moment. As the mixture is cooled by mixing with more air, the uranium oxide will then condense. The calculation which I have done is for a rare case of uranium being vapourised and then oxidised, this would happen in reactive spluttering where in an argon/oxygen gas at low preasure uranium atoms are spalled off of a surface by plasma discharge. So I think that it is reasonable to assume that uranium trioxide gas can be formed (for a moment) by burning uranium under a set of idealised conditions, but I expect that it will rapidly condense onto a surface.
Anyone who wants to is welcome to check my maths:) Cadmium
Flame temperature data. -- James S. 20:14, 17 March 2006 (UTC)
Willson has done no research on UO3 he only quotes the ackeman paper nothing more. -- Stone 08:53, 23 March 2006 (UTC)
Lets start wit the equation it self: can be found in [3]
log p= (((1.821 ± 0.075)· 104)/T) + 6.84 ± 0.58 log p= (((1.856 ± 0.016)· 104)/T) + 6.928 ± 0.103
I choose the first equation because it gives the higher pressure for UO3 gas.
log p= (((1.821 ± 0.075)· 104)/T) + 6.84 ± 0.58
Lets state 300K as the temperature (26°C or so)
putting in the numbers gives:
log p = -53.86
put both sides in the power over ten (native speaker needed)
p = 10-53.86 atm
p = 1.38 · 10-54 atm
convert from atm to Pa (1 atm = 101325 Pa)
p = 1.3985 · 10-49 Pa (N/m2)
Assuming that the laws of ideal gas are good for this problem
(which they are not, because the the condensation and the interaction between the molecules give even lower pressure for real gas at lower temperature than expected by the ideal gas euqaution)
p V= n R T
n = (p · V) / (R · T)
n =(1.3985 · 10-49 N/m2 · 1 m3)/ (8.314472 J · K-1 · mol-1 · 300 K)
n = 5.57 · 10-53 mol
so this is the number of mol per cubic meter of uranium trioxide.
1 mol = 6.023 · 1023 particles
So to get the number of particles in one cubic meter simpl multipie the numbers.
6.023 · 1023 5.57 · 10-53 = 3.35 · 10-29 particle per m3
Other way to point this numer is you need 2.98 · 1028 m3 to find on single atom of UO3.
Volume of earth 1.0832×1012 km3 = 1.0832×1021 m3 so even if the whole earth would be atmosphere there would be no molecule founnd in it. 600 times earth volume and you find your UO3.
Where is your calculation on this topic?
-- Stone 08:53, 23 March 2006 (UTC)
The pressure is absulutly independent on the surface! It is only the equilibrium reached faster if the surface is higher! A bound of sugar dissolves in a litre of water faster if you grind it, but the amount of sugar in the water will be in the end the same. Mass action there is no surface in this law for solution and condensation. -- Stone 11:46, 23 March 2006 (UTC)
Under the above theory of sublimation-as-combustion, the nearly exclusive combustion product would be uranium(0) metal. Sorry, that is incorrect. Please try again. -- 171.64.133.83 19:08, 23 March 2006 (UTC)
So is there any shred of a doubt in anyone's mind that UO3(g) is NOT a factor in uranium combustion in open air? Can we put this to rest, and remove its mention from the article now? -- DV8 2XL 19:11, 23 March 2006 (UTC)
The amount of dust makes a huge difference, but doesn't affect the solubility very much. There are probably some in your lungs right now. I am having trouble figuring out exactly how many because some of the statistics involve catastrophic distributions (lognornals on integers with deviations or variances greater than their means or modes) and I do not know how to transit confidence interval bounds through them yet. -- James S. 20:39, 24 March 2006 (UTC)
It's not a personal attack to point out that someone is wrong, or confused. You are in the wrong here James, plain and simple, you have been told over and over again by everyone that has looked at this subject. We have all taken great pains to look over your source material and point out where you have gone wrong in your reasoning and understanding of the fundamentals, yet you still claim that your thesis is the right one and that it is properly sourced when it has been clearly demonstrated erroneous. Your are not a scientist, not by station, not by knowledge, not by conduct. You are now simply just another pathetic crank. -- DV8 2XL 22:51, 24 March 2006 (UTC)
First I don't believe your are sorry at all for driving me off - in fact I believe that you have entered this argument at this late date to try and repeat it.
I have called James out for what he is; he has shown absolutely no understanding of what many people have gone to the trouble to show him by calculation, and more telling he has not provided counter arguments using calculation himself, nor are you. He is obstreperously holding on to a position in the face of a monumental amount of proof that he is wrong. Because like you he cares nothing of science, truth or reason beyond the needs of a political agenda.
You also know absolutely nothing about the science or you would be able to follow the arguments that have been posted above. What you are talking about has absolutely nothing to do with the issues here at all since we are discussing the formation of one species, not the distribution of combustion products. And your arguments and examples are even more ridiculous than his -- DV8 2XL 05:10, 25 March 2006 (UTC)
DV82XL, thanks for the references (on my talk page) to prior history. Again, I'm a little puzzled what is going on here. In the past there seems to have been a strong argument over whether depleted uranium is a hazard, and there was much spirited debunking! On this page, that debate seems to have taken the form of an argument over whether uranium trioxide gas is produced by combustion of depleted uranium in air. That notion (that uranium trioxide gas is a final combustion product) seems to have been debunked rather thoroughly.
But I do not see anything that indicates UO3 is not produced at all by combustion of metallic uranium - clearly that will take a trip to the library to check some of the references in the debate.
Meanwhile, granting (for the sake of argument only) that UO3 might actually be produced by combustion (albeit perhaps in solid form as a kind of soot, or perhaps as a low-quantity side product compared to the full oxide), I don't see anything else in the article that seems out in left field. Is that the only thing you're currently concerned about in this particular article (never mind what went on over depleted uranium)?
Cheers, zowie 14:55, 25 March 2006 (UTC)
UO3 Gas. My personal conclusion.
Simple way to pu it: If water vapor is produced by a fire or other combustion the condensation rate and temperature is the same as if you produce the vapor by subliamtion or boiling. The Born haber cycle states this and makes nothing other possible.-- Stone 06:35, 27 March 2006 (UTC)
To the lamp black argumentation! You do exact the same like James! The lamp black is carbon produced by sublimation and part oxidation of organic materials. This is not C (gas). C gas is not stable in any conditions in air. So claiming that C gas is in the air for weeks is simply false! But you can do it as long its not in the carbon page. The lamp black you get from Borneo or from your oil lamp is graphit particles nothing more and nothing less. Particles can travel the world for years nobody will deny the fact and your obvious was never denied, but: THERE ARE NO GAS MOLECULES AROUND! The condensation takes place at temperatures where the equilibrium is reached fast and all the UO3 condenses and it forms small particles which can fly around similar to the gas molecules, but they are no gas and will never be.-- Stone 06:46, 27 March 2006 (UTC)
TO James. Where is the literature profe for the 5-6 Angström particles and their non condensation you claim earlier!-- Stone 06:46, 27 March 2006 (UTC)
Introduction
At the moment, the introduction stands as:
I was reading
Greenwood & Earnshaw (p. 1268) - here is their introduction to uranium trioxide:
Can we put in the fact that it is γ-UO3 that is obtained by heating uranyl nitrate at 400°C? -- Ben 13:11, 25 March 2006 (UTC).
I think we should move the words toxic and teratogenic to a subsection, because it's confusing to have physical and chemical properties listed in between the effects of UO3 on humans. To those of you who are thinking 'but UO3 is so toxic and teratogenic, we must make this clear right at the start of the article', I would ask you to take a look at isotretinoin. I found this from the article on teratogenesis - where it lists isotretinoin as a very strong teratogen. Even though its teratogenicity is very important, it is not discussed in the introduction in its article, but in a subsection further down.
I think this layout would help make the UO3 article more NPOV, as it would have the same emphasis on tetatogenicity as other articles. I am refraining from making this change immediately because of the great deal of dispute that exists surrounding this article. -- Ben 13:11, 25 March 2006 (UTC).
Structure
I've added a PNG of a UO3 molecule. I'm not sure if it is right. I know that UO3 is mostly encountered as a solid and as such has a crystal structure not represented by my diagram. I'll see if I can make a model of that too. I'm having trouble finding details of the structure of solid UO3 - there are seven forms apparently. If anyone can send me a pdb, mol, xyz or other file that iMol can read of the crystal structure of UO3, I'll happily make a PNG of this and upload it here.
Sorry for the long comment. I'm hoping for a happy ending to the wars on this article! -- Ben 13:11, 25 March 2006 (UTC).
Acta Cryst. (1963). 16, 993 The Crystal Structure of γ-UOs BY R. ENGIVKANN AND P. I~. DE WOLFF
Acta Cryst. (1966). 20, 292 The Crystal Structure of High-Pressure UO3* BY S. SIEGEL, H. HOEKSTRA AND E. SHERRY Acta Cryst. (1966). 21, 589 The Structure of β-UO3* BY P. C. DEBETS -- Stone 06:55, 27 March 2006 (UTC) UO3 vs. O3U
I put back in the NIST reference that was kindly added earlier, as NIST is widely recognized as an authoritative source. If they refer to the molecule as O3U then it is fair to say that at least a significant part of the scientific establishment calls it that. zowie 16:28, 26 March 2006 (UTC)
Where is the reference for the structure? This looks not very good for me! Hybridisation and the lone-pairs should also be shown, to get a picture if this structure could be right. Gaspahse spectroscopy for structural purpose was in no paper I found on my search for uraniumoxide gas. Even the the MS-spectroscopy papers do not state any structural data. -- Stone 08:03, 27 March 2006 (UTC)
The structure from Gmelin of the molecular UO3 is from deep temperature matrix experiments. UO3 is incorporated of a solid argon matrix which is inreactive against nearly everything at low temperatures. The Raman and IR spectroscopy date suggest that the linear UO22+ with a O2- on the side which gives T-shaped molecule. The trigonal planar (D3d) structure was also proposed but only favoured by calculations. The T-shape is only estimated by the symmetry of the vibrations shown in Raman and IR. (Comment for James: Raman is no MS spectroscopy, it is comparable to IR spectroscopy) The deep temperature argon matrix experiments are the state of the art experiment for instable molecules to be detected. In the matrix the molecules can not react with each other because they are separated by inreactive noble gas molecules und the necessary activation energy is not available at deep temperatures. (kinetically and thermodynamically hindered reaction conditions) The concentration of molecules can be high, because of that Raman and IR are able to detect them.
X-ray crystal structure is only possible for the solid and shows for gamma UO3 two types of uranium atoms the hexa (octaedric) coordinated in. The structure can described as UO22+ UO42-. In beta UO3 three types of uranium atoms are present. Two forming Uranyl with four oxygens in bigger distance. One with a octaedric surrounding and two with a octaedric surrounding connected over one oxygen. Which gives a 2(UO22+) UO42- U3O72- as a good suggestion.
Ackermann: These observations suggest the possibility that UO3 is the principal species in equilibrium with U3O8 under the experimental conditions. This is weak not a clear statement, at best.