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Over the next several days/several edits I'm going to try and overhaul this article and make it more comprehensible. I've got it on watch, so any sugestions along the way are welcome. — Preceding unsigned comment added by EagleFalconn ( talk • contribs)
I think that since we've established that the page needs some work, but is for the most part better than it was, I'm going to remove the attention tag.
EagleFalconn 01:46, 6 Dec 2004 (UTC)
Ok, I'm way late into this conversation, and I came to discuss my other topic below, but I'll leave my thoughts on this issue anyway. The current thinking is that the best articles are written in Wikipedia:Summary style, where the main article has the overview and relevant details to fit in about 30k of text, and the various subsections for more detailed topics are summaries of more detailed daughter articles. Then the lead section for the main article is a overview summary designed to ease a reader into the whole topic. Using good summary style has a number of advantages, including avoiding having duplicate articles covering related material in different ways. Ideally all of the important ways of looking at the topic should be summarized in the main article, and the daughter articles would cover the details. Yes the summary subsections cover the same material as the daughter articles, but that redundancy is inevitable and even good. It allows a topic to be covered on many levels, from the superficial to the gory details, and satisfy everyone from the novice to the expert. It's not easy of course, but who said any great article was. Suffice it to say that there is a lot of consensus for this way of organizing the best articles. Thanks - Taxman Talk 23:59, Jun 9, 2005 (UTC)
A problem with hybridization is that it is really only used in elementary texts, and this leads to confusion. Thus
clearly the guys who are referring to molecular orbitals and hybridization have something in mind, but as the terms are properly - and widely - used, they are not related at all.
.. more thoughts later...-- Ian 12:08, 31 Jan 2005 (UTC)
PS: should we settle on hybridization or hybridisation? The former is used in most books I've seen (both US and UK)....
I'm going to have to disagree Ian...I perform computational chemistry research at Indiana State University and orbital hybridization is most definetely a theory that is still used. For example, the NBO package which uses the schrodinger equation to evaluate the bonding orbitals of a molecule is cutting edge stuff. It displays bonds in terms of hybrids. Furthermore, d orbital hybrids are not debunked in any way...could you cite some sources as to your opinions because those are both certainly news to me. Also, since this is the English Wikipedia, I would assume that it is US/UK centric, and should be spelled with a Z. EagleFalconn 02:39, 1 Feb 2005 (UTC)
I too am in computational chemistry research, so maybe we should work something out wihtout clogging up the main pages. I've put some sources and comments on your talk page. Suffice to say here that NBO is an interpretation of results that come from wavefunctions, cast especially to bring in hybridization - it certainly isn't there in the first place! I too reckon Z rather than S - but the article doesn't! -- Ian 15:19, 1 Feb 2005 (UTC)
I prefer using "hybridization" rather than "hybridisation". -- HappyCamper 15:25, 30 July 2005 (UTC)
(moved here from main page Dirk Beetstra T C 08:47, 12 December 2006 (UTC)): The word hybridisation is spelled wrong many times in this article and should be replaced with the correct spelling hybridization.—Preceding unsigned comment added by 70.243.254.146 ( talk • contribs)
Hybridise certainly is an English word. Being in Australia I only have access to the Macquarie Dictionary, but the entry there is:
This of course is where the word in chemistry came from. -- Bduke 22:26, 30 November 2007 (UTC)
I'm in the US, so I'm happy with the zed, I mean the zee. However, regardless of one's leaning on this spelling issue, it seems reasonable to have uniformity within the page. This article apparently was started with hybridisation, so that's what I've changed everything to. -- Astrochemist 02:26, 29 April 2007 (UTC)
One guideline at WP:ENGVAR says "Articles should use the same spelling system and grammatical conventions throughout." Since this particular article was started with British English, are there other words in it that should be changed too? Someone from the UK, Canada, and so on could probably spot them faster then me. -- Astrochemist 02:31, 30 April 2007 (UTC)
Since Wikipedia and Wikimedia are both American, the articles should be spelled in American English. You wouldn't find colour in an American book, and you wouldn't find color in an English text. The Brits have enough dictionaries/encyclopedias, wikipedia is ours! Also, hybridisation looks really ugly. —Preceding unsigned comment added by 152.3.152.242 ( talk)
I changed it Look here "American spelling accepts only -ize endings in most cases, such as organize, recognize, and realize.[48] British usage accepts both -ize and the more French-looking -ise " It needs to be ize...if we are looking for a generally more accepted term, ize works for everyone. Bozgoalie ( talk) 22:37, 16 November 2009 (UTC)
In the methane hybridisation picture towards the bottom of the article, the nodes appear to coincide with the nucleus which is, I am assured, incorrect. The nucleus should lie a little way into the minor lobe. Mullet 13:24, 27 October 2005 (UTC)
I have a question on this quote from the article: "Carbon will never form any less than four bonds unless it is given no other choice, which seldom occurs."
I have been taught that carbon ALWAYS forms four bonds, now this may be because I'm not a chem major yet and it's somethign to be viewed later, but could anyone verify and confirm wether the quote is accurate?
The PA 01:40, 8 December 2005 (UTC)
I removed this from the introductory paragraph:
That is in contradiction with the VSEPR theory, in which hybridization of atoms of groups 5 and 6 are useful. Please do some research before putting it back in. -- Felix Wan 01:21, 3 February 2006 (UTC)
Well, well, well...I think I might be bold on this article.
At minimum, I'd like to add these to the bottom. (And they are redlinks too!)-- HappyCamper 14:37, 13 May 2006 (UTC)
Hi Smokefoot, Hybridization theory superseded by MO theory? I suggest that the orbital hybridization page starts with an explanation of the concept followed by a criticism section and not the other way around. I notice that the MO theory page completely lacks elemental MO diagrams let alone that of methane. I have seen this before in the Banana bond page where one editor was so certain that Banana bonds were made redundant by Walsh orbitals that he advised wiki readers to forget about banana bonds altogether. The Walsh orbital page has yet to be written.... My suggestions: we should try to find a methane photoelectron pic like this one here , explain how it is possible to fix orbital hybridization theory in order to accommodate this uncomfortable truth and move criticism part to the bottom, and also start working on a MO diagram page V8rik 15:46, 16 September 2006 (UTC)
(If you can tell me how to better save this ChemDraw, that would be appreciated, it looks grainy - I just saved ChemDraw as .png). Is this the kind of graphic that you were thinking of? I also have a drawing ( ) somewhere in wikispace but I dont know how to work with it - it does not seem to load. Possibly too big. In any case, this is the kind of stuff I have for a future MO diagram article.-- Smokefoot 18:40, 16 September 2006 (UTC)
Well, I am one of those organickers. I have read the comments on Orbital hybridization and Revision. What I do not find are arguments that use MO theory to explain the structure of methane, ethylene, acetylene, etc. These always seem to use hybridization theory. If hybridization theory is incorrect (as a model), then explain how or why MO theory is superior for the examples that seem to prefer hybridization theory. (Or perhaps I don't have a correct understanding of MO theory.)
I understand how Pauling would have adopted hybridization to explain the bonds of methane. Pauling was more pragmatic than theoretical. Without going into detail, I think there should be doubt about interpretation of black body radiation as solely electron energy levels. Doing so indicates electrons fall to higher and higher energy levels to explain the smaller energy gaps. The emission to the lowest energy level has the highest energy gap. While I agree the emission spectra follow a quantum energy pattern (Balmer and Rydberg), I don't agree that Bohr has PROVEN these energy difference do correspond with electron transitions. (I am borrowing from Gilbert Lewis's comment in his 1914 JACS paper.)
Never the less, if the point being made is that MO theory has superseded hybridization theory, then a greater explanation of why this should be the case should be made. I am not an expert, but if Pauling (and his followers) has erred, explain how. The photoelectron spectrum of methane is data. It shows there are different energy levels. How does this data prove MO theory as the sole correct explanation? How does MO theory not imply that one hydrogen is different than the other three in methane?
This is what I would like to see. If MO theory is superior for inorganic compounds and perhaps hybridization is better for small atoms, then give examples of data that are analyzed by each and a brief explanation. The point of these examples wouldn't be to answer which is superior, but rather to explain what each is and how (or why) they are best used. Petedskier ( talk) 19:46, 30 December 2011 (UTC)
The statement "hybridisation is an integral part of valence bond theory and the valence shell electron-pair repulsion (VSEPR) theory" is in fact incorrect in the latter part as the original authjor of this VSEPR approach claims that there are no orbitals involved in the theory. I do not have the references given to hand but I have no doubt they support the statement. They are however wrong as are so many others. Of course you might argue that VSEPR is incoherent if it it does not implicitly include orbitals of some kind, but that is WP:OR. Gillespie would not agree. Because this is controversal I bring it here rather than just delete it. -- Bduke 02:45, 14 December 2006 (UTC)
For experimentalists, I think that the most-common approach to VB theory is determine a structure (spectroscopic, diffraction, etc.) without reference to orbital hybridisation. As this article's "Hybridisation and molecule shape" section describes, mathematical relations exist to connect bond angles and hybridisation ratios, so if one can get (by VSEPR or measurement) a bond angle then a hybridisation ratio follows. I'm not sure how often the reverse is be done, getting a bond angle (structure) from a p-to-s ratio. There certainly are cases in EPR/ESR when isotropic and anisotropic hyperfine coupling constants can give p-to-s ratios, which in turn are converted into bond angles. (The Wikipedia EPR/ESR article is poor, so I'm not citing it. There's almost nothing there about hyperfine coupling of any type.) -- Astrochemist 02:50, 10 May 2007 (UTC)
(copied over from Talk:Sp² bond; please continue conversation here)
This article ( sp2 bond) doesn't say anything that's not already in orbital hybridization or chemical bond, and "sp2 bond" is not a common term. Actually, I'd say that the term doesn't make much sense, since the hybridization is based on the atom and not on the bond. What is more common is to say "a bond involving an sp2 atom", or an sp2-sp2 bond, (or sp2-sp3, etc.). I propose deleting this article, maybe leaving a redirect to orbital hybridization. Itub 23:10, 27 December 2006 (UTC)
3plx help!!!!
In PCl5, why can't the 4s orbitals be used in the "hybirdization"? Why is the hybridization of P in the compound as sp3d, but not s2p3( using a 3s, a 4s, 3 3p orbitals)?
What is mean by the statement: there is a conflict between 3s and 4s in the hybridization?
thx
Retrieved from " http://en.wikipedia.org/wiki/Talk:Trigonal_bipyramid_molecular_geometry"
58.152.216.169 12:05, 28 February 2007 (UTC)
Where is the statement that there is a conflict between 3s and 4s? The idea that you need sp3d to explain PCl5 is out-dated and is not needed. In fact there is evidence that the d orbitals are not involved in the bonding to anything like the extent suggested by sp3d - i.e. equal s and d involvement. Molecular orbital theory can explain the bonding without using d orbitals, but a very small d involvement does improve the picture. -- Bduke 22:07, 28 February 2007 (UTC)
The view that the d orbitals contract on the central atom when the other atoms are highly electronegative was studied over many years by David Craig but never really established. The view that the d orbitals are not involved in bonding in these molecules is now well established due in part to the work of Eric Magnussen. Most General Chemistry text are beginning to remove the sp3d2 etc hybridisation discussions. I'm just about to leave for a few days and will be on wikibreak. I'll try to look at this when I return and dig up the references. -- Bduke 22:14, 30 April 2007 (UTC)
Something in the second paragraph of that section doesn't seem right. The objection to s-p-d hybridization schemes seems to be based on the relative differences in size among those three types of atomic orbitals. There is then a comment about d orbitals contracting so that they are closer to the s and p types, in radial distance. However, won't this same formal-charge argument also apply to the s and p orbitals, contracting them beyond the size needed for hybrids to form with d orbitals? None of this is obvious to me, one way or another, except that the contraction argument sounds more like an after-the-fact rationalization than an a priori explanation. No, I don't have an answer and I'm not arguing one way or the other. Perhaps someone could add references for this section of the article. -- Astrochemist 00:48, 1 May 2007 (UTC)
How about an image of an sp hybrid orbital? It looks essentially like a p orbital, but it's different. 168.122.108.87 ( talk) 20:19, 18 September 2008 (UTC)
Water is an unfortunate choice of an example for this article, since water isn't actually an sp3 hybrid. This can be (and indeed has been) easily proven with XPS spectroscopy. The fact that its geometry happens to be close to what would be predicted by an sp3 hybrid is merely a coincidence.
Just using carbons is a cop out. —Preceding unsigned comment added by Inthemtns ( talk • contribs) 19:20, 16 October 2009 (UTC)
I have added a "citation needed" tag to the sentence "The combination of these forces creates new mathematical functions known as hybridised orbitals", although it also refers to the discussion in the paragraph above leading up to that statement. I would like to know whether that explanation appears in any textbook or paper. It seems to me to be quite incorrect as it implies that hybrid orbitals are the result of physical forces. The mainstream view is that hybridisation is just a mathematical process in valence bond theory to get four distinct bonds and nothing more than that. The fact that we can quite well explain the bonding in methane without using hybrids shows that hybridisation is not a physical process. I will try to fix this but I am curious to know whether the explanation in the article has been seriously put forward. -- Bduke (Discussion) 23:02, 11 January 2010 (UTC)
Let me try to discuss the last two edits by myself and DMacks. First, "The hydrogen-carbon bonds are all of equal strength and length, which agrees with experimental data" is true but there is no basis to say it at the point where it now is as the hybridisation theory is not yet explained for ethene. It needs to be moved down to after the theory is explained. Second, The sentence above is not clear. Second, I fail to see what "(however, the π bond may or may not occur)" achieves. We are discussing ethene. The π bond does occur. This very simple idea has been badly explained in this article for two long. Another problems is that the diagram is not normally called a Kekule structure. I have had a go at rewriting this. The sentence on 2.5 hybridisation does not fit well in this section, but that is another matter. It must be very unclear to some readers. -- Bduke (Discussion) 07:25, 12 February 2010 (UTC)
There are two geometries associated with sp3d
The first is trigonal bipyramidal and can be thought of as sp3d(dZ2)
The Second is square-based pyramidal and can be thought of as sp3d(dx2-y2)
Also, There is an sp2d hybrid which corresponds to a square planar geometry.
This is shown on page 119 of "Inorganic Chemistry" 3rd edition by Catherine E. Housecroft and Alan G. Sharpe (2008)
I am unfamiliar with the controversies of the d orbital contributions so will not post revisions but discussion and investigation is needed. Perhaps these ideas have been dismissed, but if so i suggest mentioning them and explaining why they are no longer thought of that way.... but since this textbook is only 2 years old I am inclined to believe a certain portion of respectable chemists find these hybridizations convenient still (and if student's are being taught it, wikipedia should mention them).
Astote-ap ( talk) 08:09, 2 March 2010 (UTC)
edit:
Upon further reading of the "controversy section" of the talk page it may be best to merge this section with that.
In support of including the d-orbital hybrids i submit that the work of PD Dr. Stefan Immel be considered. at the very least added to the list of external links on the basis that it shows pictorially and mathematically the creation of Hybrid MO's from linear combination's of AO's ( http://csi.chemie.tu-darmstadt.de/ak/immel/script/redirect.cgi?filename=http://csi.chemie.tu-darmstadt.de/ak/immel/tutorials/orbitals/hybrid.html)
as noted by Dr. Immel, "hybrid orbitals are a powerful tool to describe the geometry and shape of molecules and metal complexes, yet in "real" molecules their significance may be debated. In "real" cases, someone has to refer more realistically to molecular orbitals instead. This page should give an overview on different geometries of hybrid orbitals, and the consequences for the shape of molecules."
it very well may be that the reality of d orbitals interactions are very different from Hbrid MO theory. however using Hybrid MO's with d contributions equips us with a language which can pragmatically describe the geometries of highly coordinated substances.
since Bduke is also a computational chemist, I'd like to hear in more detail his opinion before attempting to rewrite the section.
see also:
http://csi.chemie.tu-darmstadt.de/ak/immel/misc/oc-scripts/orbitals.html?id=2
Astote-ap ( talk) 09:10, 2 March 2010 (UTC)
This section is quite out of date. The consensus is now clear that d orbitals are not involved in bonding in molecules like SF6 any more than they are in SF4 and SF2. In all three cases there is a small and roughly identical participation of d orbitals as polarisation functions. This has been established in both MO, by Magnussen and others, and VB theory, by Cooper and others. I will try to rewrite it, but I am busy, so this is something of a reminder, but feel free to have a go. -- Bduke (Discussion) 00:38, 24 April 2011 (UTC)
I have removed the water controversy section, as unreferenced. It was filled with citation needed tags. I had never heard of this myself, so I dug through several texts, and I can find nothing to support the description written in the text. The best I can find is Bent's rule, a modification of hybridization theory which does not specifically say that (idealized) water is not sp3 hybridized, but does explain some of the deviations of real water's electronic structure from the idealized prediction of pure sp3 hybridization. The text I removed does not appear to be referenced. If someone can find solid refs, please feel free to add it back. -- Jayron 32 05:39, 12 May 2011 (UTC)
I removed two sections that were instructions on how to analyze structures. One didn't actually seem to address the idea of hybridization at all (maybe it was just about determining valency). The other did lead from valence-electron counting to atomic hybridization, but was simplified so much that it contradicted the analysis of water and pentavalent atoms in previous sections of this article and also the N in pyrrole (and anything else with a similar resonance effect). In addition, there were WP:TONE/ WP:NOT#HOWTO problems in the writing. DMacks ( talk) 19:11, 4 February 2012 (UTC)
Since SF6 is a regular octahedron with six equal S-F bond lengths, I question the claim of sp hybridization in this molecule. It seems to me that if only one p orbital mixed with the s, then two bonds should be shorter than the other four. Such a bond length inequality is indeed found in PF5 for which the axial (p) are longer than the equatorial (sp2).
Is there a source for the claim of sp hybridization in SF6? It is not in Magnusson's paper which is cited in this section. Dirac66 ( talk) 02:40, 8 September 2012 (UTC)
The Hypervalent molecule article describes SF6 to have 2 3c-4e bonds and 2 ordinary covalent bonds, where the ordinary covalent bonds are the ones that seem to be hybridised, judging from how in hypervalent bonding the 3c-4e bonds are always described to occupy pure p-orbitals. The equal bond lengths are explained by resonance, where all 6 bonds have equal 3c-4e, p and s character. -- Officer781 ( talk) 06:57, 9 September 2012 (UTC)
I've separated the section on misconceptions, generalized the water description to all molecules with lone pairs and created an exceptions section where those that don't follow the general scheme are listed. This is partially to decouple this page from VSEPR theory as VSEPR does not correlate to the hybridisation types as quantum chemical calculations have shown.-- Officer781 ( talk) 09:08, 11 November 2012 (UTC)
This section title is quite confusing. For main group molecules, chemists (like Pauling) thought a long time ago that hypervalence is due to expanded s2p6 octets. However as the article correctly says, this concept is now obsolete so why have a section title which says that it is true? Unfortunately some readers skim and will only read the section title, so let's have it say something which is true.
As for d(u)odectets, I have never seen this word (with any spelling) and it is not explained in the article. From the text, I think you mean that transition metal complexes tend to complete a d10s2 shell. But again, the title implies that p orbitals are important and the text explains that they are not, so the title is misleading.
Perhaps a better title would be Hypervalent molecules have s2p6 or s2d10 electron shells, if that is true. Dirac66 ( talk) 03:59, 11 December 2012 (UTC)
I do not believe that section provides an adequate summary of hybridisation in hypervalent molecules, especially since it does not fully address situations where there are no lone pairs like sulfur hexafluoride.-- Jasper Deng (talk) 05:44, 12 December 2012 (UTC)
This article and the above discussion seem confused as to the exact meaning of terms such as sp3 and sp2 especially sp. Before discussing SF6 further, we need to return to some basic definitions (which should be added to the article). The intro should specify that hybrid orbitals are linear combinations of orbitals on a given atom, introduced by Pauling as approximate description of orbitals directed towards other atoms to form bonds. And we should refrain from guessing hybridization schemes which cannot be found in reliable sources. See WP:OR.
The term sp3 does not mean just any combination of one s + three p; it implies that the weight of the s component is 1/4. The (normalized) wave function = 1/2 ψs + (31/2/2)ψpσ, where pσ is directed along the bond, or an equivalent combination of p orbitals along coordinate axes. These coefficients are fixed by symmetry for CH4, and are a good approximation for substituted methanes which also form four sigma bonds. Similarly sp2 describes an orbital which is 1/3 s, as is approximately true for C2H4 since the pi bond has no s-orbital contribution.
Molecules with lone pairs are more complex and the Pauling schemes are less exact. H2O is sometimes described as sp3, but the bond angle is less than 109.5° which implies that the AO forming the bond is less than 25% s. The true % s can be estimated from the bond angle or another physical property or from molecular orbital calculations. If for example the % s is about 20%, some describe the hybridization as sp4, which does NOT mean that 4 p AOs are involved. Similarly the sp2.5 now in the article means that the % s is 1/3.5 = 29%. An unspecified combination can be written as spx. However some (e.g. some solid-state physicists) describe this hybridation as sp, which is confusing as it suggests sp1 (50% s) as in the C2H2 molecule.
As for SF6, Pauling proposed sp3d2 which implies 17% s, 50% p, 33% d. More recent work (such as that by Magnusson cited in the article) shows that the % d is much smaller. So only 4 AOs on S are significantly populated and form 6 bonds, using 3c-4e bonds as already discussed. So what is the hybridization of the sulfur orbital which forms the 3c-4e bond on each axis? If it is called sp hybridization, that means only that there is no (significant) d participation, which is a confusing use of the term sp and to be avoided here I think. It cannot mean that the sulfur bonding orbital on each axis is 50% s as that would mean a total on the 3 axes of 150% which is impossible. As for sp3, this means 25% on each axis and 25% in a lone pair, which is possible; however the bond angle of 90° suggests pure p orbitals leaving s as a mostly non-bonding pair. So not hybridized is the simplest model, although MO calculations may indicate some small s character in the bonding MO’s. In any case we should not guess and should only include a value if we can find a source.
Finally re mention of orbitals being split into non-integer parts or “partial orbitals”. There is no such concept in quantum mechanics. If intended meaning is one (or more) lobes in space, this looks pretty in diagrams but does not correspond to a one-electron wave function which can hold two electrons. Similarly for a mathematical component of an orbital function, which also is not an electron state which can hold 2 electrons. If the term “partial orbital” has some other meaning of which I am unaware, we need a source. To describe 3c-4e bonding without talking about “partial orbitals”, just say that the orbital on the central atom can bond to 2 other atoms at once, and link to the 3c-4e article for more detail. Dirac66 ( talk) 23:01, 15 December 2012 (UTC)
Hmm. The linear independence of hypervalent molecule hybrids is a really great revelation for the hybridisation of hypervalent molecules, I must say. I was wondering, if the F p orbitals are counted in the hybridisation as part of the linearly independent set, should we revise the name of the hybridisation to reflect that? Say, sp3x2 for SF6 where x signifies ligand orbital (nonbonding) character? Or is there terminology already given in the paper by Cooper (I don't have access to papers)?-- Officer781 ( talk) 03:31, 10 January 2013 (UTC)
OK thanks. My library apparently has no access to this journal, so I will assume you have understood the article correctly and try to answer as best I can. I think you have indeed found a valid source which justifies mentioning this new notation in the article. However the traditional Pauling schemes are still much more common in organic and inorganic textbooks, and it would confuse readers to suppress them entirely. So I suggest that we mention three hybridization assignments for the hypervalent molecules and explain the problem with each.
In short, the situation seems to be that no scheme is now considered completely satisfactory and universally accepted. As for the table, logically we should place it after this discussion and have three columns, one for each scheme. Dirac66 ( talk) 00:48, 26 February 2013 (UTC)
Classification |
|
main group with lone pairs |
---|---|---|
Trigonal bipyramidal |
|
|
Square bipyramidal |
|
|
Pentagonal bipyramidal |
|
|
Square antiprismatic |
|
- |
Would something like this work? Coincidentally, the orbitals required for hybridisation for Pauling's model is the same regardless of whether the compound is main group or transition metal (if applicable).-- Officer781 ( talk) 12:50, 26 February 2013 (UTC)
Classification | Main group | Transition metal |
---|---|---|
AX2 | - |
|
AX3 | - |
|
AX4 | - |
|
AX5 |
| |
AX6 |
| |
AX7 |
| |
AX8 |
|
I'm still of the opinion that we provide this table as an alternative interpretation in the misconceptions section and keep the current system as the "best compromise" in the main table (seems to reflect what Cooper et al. was trying to convey, as arrived by both you and me together-I didn't know the orbitals had ligand character) to reflect the fact that in computational chemistry circles now the molecules are not considered to utilize both p and d orbitals simultaneously. Otherwise we have no system to describe hypervalent molecule hybridisation as there are hardly any authors of papers who put forward a systematic, organized interpretation. Only the general details like what Cooper et al. did.-- Officer781 ( talk) 12:04, 2 March 2013 (UTC)
I think that this article goes on too much about how it is taught and how it is controversial and even wrong. I believe it should focus more on what hybridisation is. — Preceding unsigned comment added by 84.210.51.171 ( talk) 21:29, 28 January 2014 (UTC)
Section spx and sdx terminology -- it says "For example, sp3 hybrids are formed from one s and three p orbitals. However, in all other cases, there is no such correspondence" and yet elsewhere in section sp2 hybrids it says "In sp2 hybridisation the 2s orbital is mixed with only two of the three available 2p orbitals:" which sounds like a correspondence to me.
In the section VSEPR electron domains and hybrid orbitals are different it says MO shows that the lone pairs in water aren't equivalent - OK - but do we have to switch to MO theory here to "prove it". Isn't there a VB explanation? ( I am thinking of Paulings original description involving no hybridisation - just p orbitals forming two bonds with hydrogens and positive charges on H atoms causing increase from 90°, with lone pairs in pz and s orbital )
Section Hybridisation and molecule shape - it says that tetrahedral AX4 involves sd3 hybridisation- is that 3d and 4s on manganese hybridising so wouldn't it be d3s? Or is this different from Paulings description?
Axiosaurus ( talk) 16:30, 12 March 2014 (UTC)
There is also the problem in MO theory for water, that while the canonical MOs do not make the "lone pairs" equivalent, transformation of the MOs to localised MOs (LMOs) can do so. Some mehtods of obtaining LMOs give equivalent lone pairs, while others do not. -- Bduke (Discussion) 21:00, 12 March 2014 (UTC)
what is the best title for a statement, do we need a new way to teach math — Preceding unsigned comment added by 198.52.30.180 ( talk) 22:20, 4 March 2015 (UTC)
I see that Officer781 has been cleaning up some of the references, which is generally good. However I disagree with the deletion of Laing's paper as a source with the edit summary we don't need two sources referring to the same thing. There can be several reasons why two sources for a given fact can be better than one:
Of course we very often only have one source because no one has bothered to find a second. But if we have two, as is the case here, it makes more sense to include both for the above reasons. So I will restore the Laing paper as a source, and retain the Weinhold group paper also. Dirac66 ( talk) 00:57, 18 March 2015 (UTC)
I readded the "AXE notation"; I found it used in both Housecraft's "Inorganic chemistry" and "Molecular orbitals of transition metal complexes" by Yves Jean. Christian75 ( talk) 10:07, 1 April 2015 (UTC)
Below is a draft of a section on hybridization of heavier p block elements. It doesn't really fit into the article as written whose focus is on ideal orthogonal "first order" hybridization which describes carbon very well but the rest of the periodic table less so. Adding this in to the article as it stands would require some re-structuring. Comments?
Hybridization of s and p orbitals to form effective sp hybrid orbitals requires that they have comparable radial extent. While 2p orbitals are on average less than 10% larger than 2s, in part attributable to the lack of a radial node in 2p orbitals, 3p orbitals which have one radial node, exceed the 3s orbitals by 20-33%. [1] The difference in extent of s and p orbitals increases further down a group. The hybridization in of atoms in chemical bonds can be analyzed by considering localized molecular orbitals, for example using natural localized molecular orbitals in a natural bond orbital (NBO) scheme. In methane, CH4, the calculated p/s ratio is approximately 3 consistent with "ideal" sp3 hybridization, whereas for silane, SiH4, the p/s ratio is closer to 2. A similar trend is seen for the other 2p elements. Substitution of fluorine for hydrogen further decreases the p/s ratio. [2]The 2p elements exhibit near ideal hybridization with orthogonal hybrid orbitals. For heavier p block elements this assumption of orthogonality cannot be justified. These deviations from the ideal hybridization were termed hybridization defects by Kutzelnigg. [3]
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Axiosaurus ( talk) 14:01, 22 April 2015 (UTC)
How will we be able to describe or find hybridization of certain compound like C2H4,C2H6,C2H2 by using electron configuration alone?without use of orbital diagram. Alishasapkota ( talk) 12:03, 2 July 2016 (UTC)
If something is not mentioned in the body of the article, it should not be mentioned in the lead section. Also, there should not be blue links in bold face in the article lead. Seems that at least two editors are not aware of these basic standards. 95.145.130.4 ( talk) 21:40, 4 May 2017 (UTC)
@ Dirac66: I noticed that the square planar hybridisation angle was changed from 109.5 and 180 to 90. I placed the interorbital angles in the hybridisation row because it reflects the ideal interorbital angle calculated by the formula instead of the actual molecular angle (109.5 comes from the positive form of the formula while 180 comes from the negative form). That's why 70.5 is included together with 109.5 for the sd3 tetrahedral even though it is not present in the final molecule. Also, trigonal pyramidal and trigonal prismatic complexes frequently have larger bond angles than the ideal orbital angle because of ligand repulsion. Thoughts?-- Officer781 ( talk) 09:39, 14 May 2020 (UTC)
Why is methylene mentioned under the header sp3? I was trying to close out the discrepancy to remove the {{contradictory}} tag, but the alt-text is kind of a confusing run-on sentence that mentions a lot of things that aren't there, e.g., the bond angle of carbene. Is the use of the unfavorable structure useful at all as part of the explanation? Reconrabbit ( talk| edits) 14:44, 20 December 2023 (UTC)
@ Reconrabbit: I have now clarified this to distinguish between the hypothetical non-hybridized 90° molecule and the real hybridized 102° molecule. And I have placed the alt-text in the article where it is more legible. Dirac66 ( talk) 17:36, 16 March 2024 (UTC)
how to calculate unit vector 137.196.0.34 ( talk) 06:43, 16 April 2024 (UTC)
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Over the next several days/several edits I'm going to try and overhaul this article and make it more comprehensible. I've got it on watch, so any sugestions along the way are welcome. — Preceding unsigned comment added by EagleFalconn ( talk • contribs)
I think that since we've established that the page needs some work, but is for the most part better than it was, I'm going to remove the attention tag.
EagleFalconn 01:46, 6 Dec 2004 (UTC)
Ok, I'm way late into this conversation, and I came to discuss my other topic below, but I'll leave my thoughts on this issue anyway. The current thinking is that the best articles are written in Wikipedia:Summary style, where the main article has the overview and relevant details to fit in about 30k of text, and the various subsections for more detailed topics are summaries of more detailed daughter articles. Then the lead section for the main article is a overview summary designed to ease a reader into the whole topic. Using good summary style has a number of advantages, including avoiding having duplicate articles covering related material in different ways. Ideally all of the important ways of looking at the topic should be summarized in the main article, and the daughter articles would cover the details. Yes the summary subsections cover the same material as the daughter articles, but that redundancy is inevitable and even good. It allows a topic to be covered on many levels, from the superficial to the gory details, and satisfy everyone from the novice to the expert. It's not easy of course, but who said any great article was. Suffice it to say that there is a lot of consensus for this way of organizing the best articles. Thanks - Taxman Talk 23:59, Jun 9, 2005 (UTC)
A problem with hybridization is that it is really only used in elementary texts, and this leads to confusion. Thus
clearly the guys who are referring to molecular orbitals and hybridization have something in mind, but as the terms are properly - and widely - used, they are not related at all.
.. more thoughts later...-- Ian 12:08, 31 Jan 2005 (UTC)
PS: should we settle on hybridization or hybridisation? The former is used in most books I've seen (both US and UK)....
I'm going to have to disagree Ian...I perform computational chemistry research at Indiana State University and orbital hybridization is most definetely a theory that is still used. For example, the NBO package which uses the schrodinger equation to evaluate the bonding orbitals of a molecule is cutting edge stuff. It displays bonds in terms of hybrids. Furthermore, d orbital hybrids are not debunked in any way...could you cite some sources as to your opinions because those are both certainly news to me. Also, since this is the English Wikipedia, I would assume that it is US/UK centric, and should be spelled with a Z. EagleFalconn 02:39, 1 Feb 2005 (UTC)
I too am in computational chemistry research, so maybe we should work something out wihtout clogging up the main pages. I've put some sources and comments on your talk page. Suffice to say here that NBO is an interpretation of results that come from wavefunctions, cast especially to bring in hybridization - it certainly isn't there in the first place! I too reckon Z rather than S - but the article doesn't! -- Ian 15:19, 1 Feb 2005 (UTC)
I prefer using "hybridization" rather than "hybridisation". -- HappyCamper 15:25, 30 July 2005 (UTC)
(moved here from main page Dirk Beetstra T C 08:47, 12 December 2006 (UTC)): The word hybridisation is spelled wrong many times in this article and should be replaced with the correct spelling hybridization.—Preceding unsigned comment added by 70.243.254.146 ( talk • contribs)
Hybridise certainly is an English word. Being in Australia I only have access to the Macquarie Dictionary, but the entry there is:
This of course is where the word in chemistry came from. -- Bduke 22:26, 30 November 2007 (UTC)
I'm in the US, so I'm happy with the zed, I mean the zee. However, regardless of one's leaning on this spelling issue, it seems reasonable to have uniformity within the page. This article apparently was started with hybridisation, so that's what I've changed everything to. -- Astrochemist 02:26, 29 April 2007 (UTC)
One guideline at WP:ENGVAR says "Articles should use the same spelling system and grammatical conventions throughout." Since this particular article was started with British English, are there other words in it that should be changed too? Someone from the UK, Canada, and so on could probably spot them faster then me. -- Astrochemist 02:31, 30 April 2007 (UTC)
Since Wikipedia and Wikimedia are both American, the articles should be spelled in American English. You wouldn't find colour in an American book, and you wouldn't find color in an English text. The Brits have enough dictionaries/encyclopedias, wikipedia is ours! Also, hybridisation looks really ugly. —Preceding unsigned comment added by 152.3.152.242 ( talk)
I changed it Look here "American spelling accepts only -ize endings in most cases, such as organize, recognize, and realize.[48] British usage accepts both -ize and the more French-looking -ise " It needs to be ize...if we are looking for a generally more accepted term, ize works for everyone. Bozgoalie ( talk) 22:37, 16 November 2009 (UTC)
In the methane hybridisation picture towards the bottom of the article, the nodes appear to coincide with the nucleus which is, I am assured, incorrect. The nucleus should lie a little way into the minor lobe. Mullet 13:24, 27 October 2005 (UTC)
I have a question on this quote from the article: "Carbon will never form any less than four bonds unless it is given no other choice, which seldom occurs."
I have been taught that carbon ALWAYS forms four bonds, now this may be because I'm not a chem major yet and it's somethign to be viewed later, but could anyone verify and confirm wether the quote is accurate?
The PA 01:40, 8 December 2005 (UTC)
I removed this from the introductory paragraph:
That is in contradiction with the VSEPR theory, in which hybridization of atoms of groups 5 and 6 are useful. Please do some research before putting it back in. -- Felix Wan 01:21, 3 February 2006 (UTC)
Well, well, well...I think I might be bold on this article.
At minimum, I'd like to add these to the bottom. (And they are redlinks too!)-- HappyCamper 14:37, 13 May 2006 (UTC)
Hi Smokefoot, Hybridization theory superseded by MO theory? I suggest that the orbital hybridization page starts with an explanation of the concept followed by a criticism section and not the other way around. I notice that the MO theory page completely lacks elemental MO diagrams let alone that of methane. I have seen this before in the Banana bond page where one editor was so certain that Banana bonds were made redundant by Walsh orbitals that he advised wiki readers to forget about banana bonds altogether. The Walsh orbital page has yet to be written.... My suggestions: we should try to find a methane photoelectron pic like this one here , explain how it is possible to fix orbital hybridization theory in order to accommodate this uncomfortable truth and move criticism part to the bottom, and also start working on a MO diagram page V8rik 15:46, 16 September 2006 (UTC)
(If you can tell me how to better save this ChemDraw, that would be appreciated, it looks grainy - I just saved ChemDraw as .png). Is this the kind of graphic that you were thinking of? I also have a drawing ( ) somewhere in wikispace but I dont know how to work with it - it does not seem to load. Possibly too big. In any case, this is the kind of stuff I have for a future MO diagram article.-- Smokefoot 18:40, 16 September 2006 (UTC)
Well, I am one of those organickers. I have read the comments on Orbital hybridization and Revision. What I do not find are arguments that use MO theory to explain the structure of methane, ethylene, acetylene, etc. These always seem to use hybridization theory. If hybridization theory is incorrect (as a model), then explain how or why MO theory is superior for the examples that seem to prefer hybridization theory. (Or perhaps I don't have a correct understanding of MO theory.)
I understand how Pauling would have adopted hybridization to explain the bonds of methane. Pauling was more pragmatic than theoretical. Without going into detail, I think there should be doubt about interpretation of black body radiation as solely electron energy levels. Doing so indicates electrons fall to higher and higher energy levels to explain the smaller energy gaps. The emission to the lowest energy level has the highest energy gap. While I agree the emission spectra follow a quantum energy pattern (Balmer and Rydberg), I don't agree that Bohr has PROVEN these energy difference do correspond with electron transitions. (I am borrowing from Gilbert Lewis's comment in his 1914 JACS paper.)
Never the less, if the point being made is that MO theory has superseded hybridization theory, then a greater explanation of why this should be the case should be made. I am not an expert, but if Pauling (and his followers) has erred, explain how. The photoelectron spectrum of methane is data. It shows there are different energy levels. How does this data prove MO theory as the sole correct explanation? How does MO theory not imply that one hydrogen is different than the other three in methane?
This is what I would like to see. If MO theory is superior for inorganic compounds and perhaps hybridization is better for small atoms, then give examples of data that are analyzed by each and a brief explanation. The point of these examples wouldn't be to answer which is superior, but rather to explain what each is and how (or why) they are best used. Petedskier ( talk) 19:46, 30 December 2011 (UTC)
The statement "hybridisation is an integral part of valence bond theory and the valence shell electron-pair repulsion (VSEPR) theory" is in fact incorrect in the latter part as the original authjor of this VSEPR approach claims that there are no orbitals involved in the theory. I do not have the references given to hand but I have no doubt they support the statement. They are however wrong as are so many others. Of course you might argue that VSEPR is incoherent if it it does not implicitly include orbitals of some kind, but that is WP:OR. Gillespie would not agree. Because this is controversal I bring it here rather than just delete it. -- Bduke 02:45, 14 December 2006 (UTC)
For experimentalists, I think that the most-common approach to VB theory is determine a structure (spectroscopic, diffraction, etc.) without reference to orbital hybridisation. As this article's "Hybridisation and molecule shape" section describes, mathematical relations exist to connect bond angles and hybridisation ratios, so if one can get (by VSEPR or measurement) a bond angle then a hybridisation ratio follows. I'm not sure how often the reverse is be done, getting a bond angle (structure) from a p-to-s ratio. There certainly are cases in EPR/ESR when isotropic and anisotropic hyperfine coupling constants can give p-to-s ratios, which in turn are converted into bond angles. (The Wikipedia EPR/ESR article is poor, so I'm not citing it. There's almost nothing there about hyperfine coupling of any type.) -- Astrochemist 02:50, 10 May 2007 (UTC)
(copied over from Talk:Sp² bond; please continue conversation here)
This article ( sp2 bond) doesn't say anything that's not already in orbital hybridization or chemical bond, and "sp2 bond" is not a common term. Actually, I'd say that the term doesn't make much sense, since the hybridization is based on the atom and not on the bond. What is more common is to say "a bond involving an sp2 atom", or an sp2-sp2 bond, (or sp2-sp3, etc.). I propose deleting this article, maybe leaving a redirect to orbital hybridization. Itub 23:10, 27 December 2006 (UTC)
3plx help!!!!
In PCl5, why can't the 4s orbitals be used in the "hybirdization"? Why is the hybridization of P in the compound as sp3d, but not s2p3( using a 3s, a 4s, 3 3p orbitals)?
What is mean by the statement: there is a conflict between 3s and 4s in the hybridization?
thx
Retrieved from " http://en.wikipedia.org/wiki/Talk:Trigonal_bipyramid_molecular_geometry"
58.152.216.169 12:05, 28 February 2007 (UTC)
Where is the statement that there is a conflict between 3s and 4s? The idea that you need sp3d to explain PCl5 is out-dated and is not needed. In fact there is evidence that the d orbitals are not involved in the bonding to anything like the extent suggested by sp3d - i.e. equal s and d involvement. Molecular orbital theory can explain the bonding without using d orbitals, but a very small d involvement does improve the picture. -- Bduke 22:07, 28 February 2007 (UTC)
The view that the d orbitals contract on the central atom when the other atoms are highly electronegative was studied over many years by David Craig but never really established. The view that the d orbitals are not involved in bonding in these molecules is now well established due in part to the work of Eric Magnussen. Most General Chemistry text are beginning to remove the sp3d2 etc hybridisation discussions. I'm just about to leave for a few days and will be on wikibreak. I'll try to look at this when I return and dig up the references. -- Bduke 22:14, 30 April 2007 (UTC)
Something in the second paragraph of that section doesn't seem right. The objection to s-p-d hybridization schemes seems to be based on the relative differences in size among those three types of atomic orbitals. There is then a comment about d orbitals contracting so that they are closer to the s and p types, in radial distance. However, won't this same formal-charge argument also apply to the s and p orbitals, contracting them beyond the size needed for hybrids to form with d orbitals? None of this is obvious to me, one way or another, except that the contraction argument sounds more like an after-the-fact rationalization than an a priori explanation. No, I don't have an answer and I'm not arguing one way or the other. Perhaps someone could add references for this section of the article. -- Astrochemist 00:48, 1 May 2007 (UTC)
How about an image of an sp hybrid orbital? It looks essentially like a p orbital, but it's different. 168.122.108.87 ( talk) 20:19, 18 September 2008 (UTC)
Water is an unfortunate choice of an example for this article, since water isn't actually an sp3 hybrid. This can be (and indeed has been) easily proven with XPS spectroscopy. The fact that its geometry happens to be close to what would be predicted by an sp3 hybrid is merely a coincidence.
Just using carbons is a cop out. —Preceding unsigned comment added by Inthemtns ( talk • contribs) 19:20, 16 October 2009 (UTC)
I have added a "citation needed" tag to the sentence "The combination of these forces creates new mathematical functions known as hybridised orbitals", although it also refers to the discussion in the paragraph above leading up to that statement. I would like to know whether that explanation appears in any textbook or paper. It seems to me to be quite incorrect as it implies that hybrid orbitals are the result of physical forces. The mainstream view is that hybridisation is just a mathematical process in valence bond theory to get four distinct bonds and nothing more than that. The fact that we can quite well explain the bonding in methane without using hybrids shows that hybridisation is not a physical process. I will try to fix this but I am curious to know whether the explanation in the article has been seriously put forward. -- Bduke (Discussion) 23:02, 11 January 2010 (UTC)
Let me try to discuss the last two edits by myself and DMacks. First, "The hydrogen-carbon bonds are all of equal strength and length, which agrees with experimental data" is true but there is no basis to say it at the point where it now is as the hybridisation theory is not yet explained for ethene. It needs to be moved down to after the theory is explained. Second, The sentence above is not clear. Second, I fail to see what "(however, the π bond may or may not occur)" achieves. We are discussing ethene. The π bond does occur. This very simple idea has been badly explained in this article for two long. Another problems is that the diagram is not normally called a Kekule structure. I have had a go at rewriting this. The sentence on 2.5 hybridisation does not fit well in this section, but that is another matter. It must be very unclear to some readers. -- Bduke (Discussion) 07:25, 12 February 2010 (UTC)
There are two geometries associated with sp3d
The first is trigonal bipyramidal and can be thought of as sp3d(dZ2)
The Second is square-based pyramidal and can be thought of as sp3d(dx2-y2)
Also, There is an sp2d hybrid which corresponds to a square planar geometry.
This is shown on page 119 of "Inorganic Chemistry" 3rd edition by Catherine E. Housecroft and Alan G. Sharpe (2008)
I am unfamiliar with the controversies of the d orbital contributions so will not post revisions but discussion and investigation is needed. Perhaps these ideas have been dismissed, but if so i suggest mentioning them and explaining why they are no longer thought of that way.... but since this textbook is only 2 years old I am inclined to believe a certain portion of respectable chemists find these hybridizations convenient still (and if student's are being taught it, wikipedia should mention them).
Astote-ap ( talk) 08:09, 2 March 2010 (UTC)
edit:
Upon further reading of the "controversy section" of the talk page it may be best to merge this section with that.
In support of including the d-orbital hybrids i submit that the work of PD Dr. Stefan Immel be considered. at the very least added to the list of external links on the basis that it shows pictorially and mathematically the creation of Hybrid MO's from linear combination's of AO's ( http://csi.chemie.tu-darmstadt.de/ak/immel/script/redirect.cgi?filename=http://csi.chemie.tu-darmstadt.de/ak/immel/tutorials/orbitals/hybrid.html)
as noted by Dr. Immel, "hybrid orbitals are a powerful tool to describe the geometry and shape of molecules and metal complexes, yet in "real" molecules their significance may be debated. In "real" cases, someone has to refer more realistically to molecular orbitals instead. This page should give an overview on different geometries of hybrid orbitals, and the consequences for the shape of molecules."
it very well may be that the reality of d orbitals interactions are very different from Hbrid MO theory. however using Hybrid MO's with d contributions equips us with a language which can pragmatically describe the geometries of highly coordinated substances.
since Bduke is also a computational chemist, I'd like to hear in more detail his opinion before attempting to rewrite the section.
see also:
http://csi.chemie.tu-darmstadt.de/ak/immel/misc/oc-scripts/orbitals.html?id=2
Astote-ap ( talk) 09:10, 2 March 2010 (UTC)
This section is quite out of date. The consensus is now clear that d orbitals are not involved in bonding in molecules like SF6 any more than they are in SF4 and SF2. In all three cases there is a small and roughly identical participation of d orbitals as polarisation functions. This has been established in both MO, by Magnussen and others, and VB theory, by Cooper and others. I will try to rewrite it, but I am busy, so this is something of a reminder, but feel free to have a go. -- Bduke (Discussion) 00:38, 24 April 2011 (UTC)
I have removed the water controversy section, as unreferenced. It was filled with citation needed tags. I had never heard of this myself, so I dug through several texts, and I can find nothing to support the description written in the text. The best I can find is Bent's rule, a modification of hybridization theory which does not specifically say that (idealized) water is not sp3 hybridized, but does explain some of the deviations of real water's electronic structure from the idealized prediction of pure sp3 hybridization. The text I removed does not appear to be referenced. If someone can find solid refs, please feel free to add it back. -- Jayron 32 05:39, 12 May 2011 (UTC)
I removed two sections that were instructions on how to analyze structures. One didn't actually seem to address the idea of hybridization at all (maybe it was just about determining valency). The other did lead from valence-electron counting to atomic hybridization, but was simplified so much that it contradicted the analysis of water and pentavalent atoms in previous sections of this article and also the N in pyrrole (and anything else with a similar resonance effect). In addition, there were WP:TONE/ WP:NOT#HOWTO problems in the writing. DMacks ( talk) 19:11, 4 February 2012 (UTC)
Since SF6 is a regular octahedron with six equal S-F bond lengths, I question the claim of sp hybridization in this molecule. It seems to me that if only one p orbital mixed with the s, then two bonds should be shorter than the other four. Such a bond length inequality is indeed found in PF5 for which the axial (p) are longer than the equatorial (sp2).
Is there a source for the claim of sp hybridization in SF6? It is not in Magnusson's paper which is cited in this section. Dirac66 ( talk) 02:40, 8 September 2012 (UTC)
The Hypervalent molecule article describes SF6 to have 2 3c-4e bonds and 2 ordinary covalent bonds, where the ordinary covalent bonds are the ones that seem to be hybridised, judging from how in hypervalent bonding the 3c-4e bonds are always described to occupy pure p-orbitals. The equal bond lengths are explained by resonance, where all 6 bonds have equal 3c-4e, p and s character. -- Officer781 ( talk) 06:57, 9 September 2012 (UTC)
I've separated the section on misconceptions, generalized the water description to all molecules with lone pairs and created an exceptions section where those that don't follow the general scheme are listed. This is partially to decouple this page from VSEPR theory as VSEPR does not correlate to the hybridisation types as quantum chemical calculations have shown.-- Officer781 ( talk) 09:08, 11 November 2012 (UTC)
This section title is quite confusing. For main group molecules, chemists (like Pauling) thought a long time ago that hypervalence is due to expanded s2p6 octets. However as the article correctly says, this concept is now obsolete so why have a section title which says that it is true? Unfortunately some readers skim and will only read the section title, so let's have it say something which is true.
As for d(u)odectets, I have never seen this word (with any spelling) and it is not explained in the article. From the text, I think you mean that transition metal complexes tend to complete a d10s2 shell. But again, the title implies that p orbitals are important and the text explains that they are not, so the title is misleading.
Perhaps a better title would be Hypervalent molecules have s2p6 or s2d10 electron shells, if that is true. Dirac66 ( talk) 03:59, 11 December 2012 (UTC)
I do not believe that section provides an adequate summary of hybridisation in hypervalent molecules, especially since it does not fully address situations where there are no lone pairs like sulfur hexafluoride.-- Jasper Deng (talk) 05:44, 12 December 2012 (UTC)
This article and the above discussion seem confused as to the exact meaning of terms such as sp3 and sp2 especially sp. Before discussing SF6 further, we need to return to some basic definitions (which should be added to the article). The intro should specify that hybrid orbitals are linear combinations of orbitals on a given atom, introduced by Pauling as approximate description of orbitals directed towards other atoms to form bonds. And we should refrain from guessing hybridization schemes which cannot be found in reliable sources. See WP:OR.
The term sp3 does not mean just any combination of one s + three p; it implies that the weight of the s component is 1/4. The (normalized) wave function = 1/2 ψs + (31/2/2)ψpσ, where pσ is directed along the bond, or an equivalent combination of p orbitals along coordinate axes. These coefficients are fixed by symmetry for CH4, and are a good approximation for substituted methanes which also form four sigma bonds. Similarly sp2 describes an orbital which is 1/3 s, as is approximately true for C2H4 since the pi bond has no s-orbital contribution.
Molecules with lone pairs are more complex and the Pauling schemes are less exact. H2O is sometimes described as sp3, but the bond angle is less than 109.5° which implies that the AO forming the bond is less than 25% s. The true % s can be estimated from the bond angle or another physical property or from molecular orbital calculations. If for example the % s is about 20%, some describe the hybridization as sp4, which does NOT mean that 4 p AOs are involved. Similarly the sp2.5 now in the article means that the % s is 1/3.5 = 29%. An unspecified combination can be written as spx. However some (e.g. some solid-state physicists) describe this hybridation as sp, which is confusing as it suggests sp1 (50% s) as in the C2H2 molecule.
As for SF6, Pauling proposed sp3d2 which implies 17% s, 50% p, 33% d. More recent work (such as that by Magnusson cited in the article) shows that the % d is much smaller. So only 4 AOs on S are significantly populated and form 6 bonds, using 3c-4e bonds as already discussed. So what is the hybridization of the sulfur orbital which forms the 3c-4e bond on each axis? If it is called sp hybridization, that means only that there is no (significant) d participation, which is a confusing use of the term sp and to be avoided here I think. It cannot mean that the sulfur bonding orbital on each axis is 50% s as that would mean a total on the 3 axes of 150% which is impossible. As for sp3, this means 25% on each axis and 25% in a lone pair, which is possible; however the bond angle of 90° suggests pure p orbitals leaving s as a mostly non-bonding pair. So not hybridized is the simplest model, although MO calculations may indicate some small s character in the bonding MO’s. In any case we should not guess and should only include a value if we can find a source.
Finally re mention of orbitals being split into non-integer parts or “partial orbitals”. There is no such concept in quantum mechanics. If intended meaning is one (or more) lobes in space, this looks pretty in diagrams but does not correspond to a one-electron wave function which can hold two electrons. Similarly for a mathematical component of an orbital function, which also is not an electron state which can hold 2 electrons. If the term “partial orbital” has some other meaning of which I am unaware, we need a source. To describe 3c-4e bonding without talking about “partial orbitals”, just say that the orbital on the central atom can bond to 2 other atoms at once, and link to the 3c-4e article for more detail. Dirac66 ( talk) 23:01, 15 December 2012 (UTC)
Hmm. The linear independence of hypervalent molecule hybrids is a really great revelation for the hybridisation of hypervalent molecules, I must say. I was wondering, if the F p orbitals are counted in the hybridisation as part of the linearly independent set, should we revise the name of the hybridisation to reflect that? Say, sp3x2 for SF6 where x signifies ligand orbital (nonbonding) character? Or is there terminology already given in the paper by Cooper (I don't have access to papers)?-- Officer781 ( talk) 03:31, 10 January 2013 (UTC)
OK thanks. My library apparently has no access to this journal, so I will assume you have understood the article correctly and try to answer as best I can. I think you have indeed found a valid source which justifies mentioning this new notation in the article. However the traditional Pauling schemes are still much more common in organic and inorganic textbooks, and it would confuse readers to suppress them entirely. So I suggest that we mention three hybridization assignments for the hypervalent molecules and explain the problem with each.
In short, the situation seems to be that no scheme is now considered completely satisfactory and universally accepted. As for the table, logically we should place it after this discussion and have three columns, one for each scheme. Dirac66 ( talk) 00:48, 26 February 2013 (UTC)
Classification |
|
main group with lone pairs |
---|---|---|
Trigonal bipyramidal |
|
|
Square bipyramidal |
|
|
Pentagonal bipyramidal |
|
|
Square antiprismatic |
|
- |
Would something like this work? Coincidentally, the orbitals required for hybridisation for Pauling's model is the same regardless of whether the compound is main group or transition metal (if applicable).-- Officer781 ( talk) 12:50, 26 February 2013 (UTC)
Classification | Main group | Transition metal |
---|---|---|
AX2 | - |
|
AX3 | - |
|
AX4 | - |
|
AX5 |
| |
AX6 |
| |
AX7 |
| |
AX8 |
|
I'm still of the opinion that we provide this table as an alternative interpretation in the misconceptions section and keep the current system as the "best compromise" in the main table (seems to reflect what Cooper et al. was trying to convey, as arrived by both you and me together-I didn't know the orbitals had ligand character) to reflect the fact that in computational chemistry circles now the molecules are not considered to utilize both p and d orbitals simultaneously. Otherwise we have no system to describe hypervalent molecule hybridisation as there are hardly any authors of papers who put forward a systematic, organized interpretation. Only the general details like what Cooper et al. did.-- Officer781 ( talk) 12:04, 2 March 2013 (UTC)
I think that this article goes on too much about how it is taught and how it is controversial and even wrong. I believe it should focus more on what hybridisation is. — Preceding unsigned comment added by 84.210.51.171 ( talk) 21:29, 28 January 2014 (UTC)
Section spx and sdx terminology -- it says "For example, sp3 hybrids are formed from one s and three p orbitals. However, in all other cases, there is no such correspondence" and yet elsewhere in section sp2 hybrids it says "In sp2 hybridisation the 2s orbital is mixed with only two of the three available 2p orbitals:" which sounds like a correspondence to me.
In the section VSEPR electron domains and hybrid orbitals are different it says MO shows that the lone pairs in water aren't equivalent - OK - but do we have to switch to MO theory here to "prove it". Isn't there a VB explanation? ( I am thinking of Paulings original description involving no hybridisation - just p orbitals forming two bonds with hydrogens and positive charges on H atoms causing increase from 90°, with lone pairs in pz and s orbital )
Section Hybridisation and molecule shape - it says that tetrahedral AX4 involves sd3 hybridisation- is that 3d and 4s on manganese hybridising so wouldn't it be d3s? Or is this different from Paulings description?
Axiosaurus ( talk) 16:30, 12 March 2014 (UTC)
There is also the problem in MO theory for water, that while the canonical MOs do not make the "lone pairs" equivalent, transformation of the MOs to localised MOs (LMOs) can do so. Some mehtods of obtaining LMOs give equivalent lone pairs, while others do not. -- Bduke (Discussion) 21:00, 12 March 2014 (UTC)
what is the best title for a statement, do we need a new way to teach math — Preceding unsigned comment added by 198.52.30.180 ( talk) 22:20, 4 March 2015 (UTC)
I see that Officer781 has been cleaning up some of the references, which is generally good. However I disagree with the deletion of Laing's paper as a source with the edit summary we don't need two sources referring to the same thing. There can be several reasons why two sources for a given fact can be better than one:
Of course we very often only have one source because no one has bothered to find a second. But if we have two, as is the case here, it makes more sense to include both for the above reasons. So I will restore the Laing paper as a source, and retain the Weinhold group paper also. Dirac66 ( talk) 00:57, 18 March 2015 (UTC)
I readded the "AXE notation"; I found it used in both Housecraft's "Inorganic chemistry" and "Molecular orbitals of transition metal complexes" by Yves Jean. Christian75 ( talk) 10:07, 1 April 2015 (UTC)
Below is a draft of a section on hybridization of heavier p block elements. It doesn't really fit into the article as written whose focus is on ideal orthogonal "first order" hybridization which describes carbon very well but the rest of the periodic table less so. Adding this in to the article as it stands would require some re-structuring. Comments?
Hybridization of s and p orbitals to form effective sp hybrid orbitals requires that they have comparable radial extent. While 2p orbitals are on average less than 10% larger than 2s, in part attributable to the lack of a radial node in 2p orbitals, 3p orbitals which have one radial node, exceed the 3s orbitals by 20-33%. [1] The difference in extent of s and p orbitals increases further down a group. The hybridization in of atoms in chemical bonds can be analyzed by considering localized molecular orbitals, for example using natural localized molecular orbitals in a natural bond orbital (NBO) scheme. In methane, CH4, the calculated p/s ratio is approximately 3 consistent with "ideal" sp3 hybridization, whereas for silane, SiH4, the p/s ratio is closer to 2. A similar trend is seen for the other 2p elements. Substitution of fluorine for hydrogen further decreases the p/s ratio. [2]The 2p elements exhibit near ideal hybridization with orthogonal hybrid orbitals. For heavier p block elements this assumption of orthogonality cannot be justified. These deviations from the ideal hybridization were termed hybridization defects by Kutzelnigg. [3]
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Axiosaurus ( talk) 14:01, 22 April 2015 (UTC)
How will we be able to describe or find hybridization of certain compound like C2H4,C2H6,C2H2 by using electron configuration alone?without use of orbital diagram. Alishasapkota ( talk) 12:03, 2 July 2016 (UTC)
If something is not mentioned in the body of the article, it should not be mentioned in the lead section. Also, there should not be blue links in bold face in the article lead. Seems that at least two editors are not aware of these basic standards. 95.145.130.4 ( talk) 21:40, 4 May 2017 (UTC)
@ Dirac66: I noticed that the square planar hybridisation angle was changed from 109.5 and 180 to 90. I placed the interorbital angles in the hybridisation row because it reflects the ideal interorbital angle calculated by the formula instead of the actual molecular angle (109.5 comes from the positive form of the formula while 180 comes from the negative form). That's why 70.5 is included together with 109.5 for the sd3 tetrahedral even though it is not present in the final molecule. Also, trigonal pyramidal and trigonal prismatic complexes frequently have larger bond angles than the ideal orbital angle because of ligand repulsion. Thoughts?-- Officer781 ( talk) 09:39, 14 May 2020 (UTC)
Why is methylene mentioned under the header sp3? I was trying to close out the discrepancy to remove the {{contradictory}} tag, but the alt-text is kind of a confusing run-on sentence that mentions a lot of things that aren't there, e.g., the bond angle of carbene. Is the use of the unfavorable structure useful at all as part of the explanation? Reconrabbit ( talk| edits) 14:44, 20 December 2023 (UTC)
@ Reconrabbit: I have now clarified this to distinguish between the hypothetical non-hybridized 90° molecule and the real hybridized 102° molecule. And I have placed the alt-text in the article where it is more legible. Dirac66 ( talk) 17:36, 16 March 2024 (UTC)
how to calculate unit vector 137.196.0.34 ( talk) 06:43, 16 April 2024 (UTC)