Talk:Orbital hybridisation

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[edit] General Discussion

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. -EagleFalconn


I think it could have more cross-referencing for the introduction, and a more focused body. There's perhaps just two much writing that's introductory, and it makes it a bigger read than necessary. I think another article shoud introduce the theory of atomic orbitals, in terms of the solutions to the Schrodinger equation for electrons. I'm going to see if something like that exists. Then, the hybridized orbitals can be introduced as a mixing of the atomic orbitals, as a linear combination of basis (linear algebra)states. This would improve the understanding that hybridized orbitals are the result of multiple basis states existing in superposition, with a significant energetic stabilization due to resonance in hybridized orbitals compared to atomic ones. So I think this could use more work (yes, I'll do some!) rmbh 07:08, Nov 21, 2004 (UTC)
Oh wow! The molecular orbital page builds all the way to hybridization, and it doesn't link to this page! There's been a lot of duplicated effort here...it's really the molecular geometry concepts that are unique to this article. The specialized hybridized orbital pages should probably be incorporated here, instead of the bulk of it, which is better explained in the molecular orbital page. rmbh 07:34, Nov 21, 2004 (UTC)
I was thinking about it over the weekend, and I was considering expanding on the bottom section and discussing in more detail the various forms of hybridization. I realized it would be fairly redundant , though I don't believe a page exists for any hybrids except sp², which right below is indicated as needing work as well. But you're right, the molecular orbital page certainly does do much of the pre-hybrid explanation work. I feel like it is explained a little better with the discussion of methane, though everything prior to where the stress exists that orbitals are models could be considered unnecessary. I think that the explanation in terms of molecular orbitals and in terms of atomic orbitals are unique and each contribute in separate ways, so there may be merits for leaving it there. Also, you have to consider: More people are familiar with atomic orbitals than molecular. I'm something of a Wikipedia noob, so perhaps this is a dumb question: Is the goal of Wikipedia with this page to educate someone who has the majority of the background knowledge for this article, or to try and relate it to someone who might not be all the way there? --EagleFalconn 15:57, 22 Nov 2004
You raise a dead-on point. I think that the Wicki approach constantly raises this issue: as a piece of unified writing, introductory material is required, but as a Wicki, introductory material is largely redundant, and clutter-promoting. After perusing Wickipedia:Forum for Encyclopedia Standards, I expect that the latter view dominates amoung Wickipedians. An obvious exception is large overview articles, like 'Canada' which may contain 'Canadian Bacon'. A subject as broad as 'quantum chemistry' probably has no such centralized article for exposition; perhaps a history article would suffice. In general, articles should be both accessible and of sufficient depth to be useful. I mean, everyone knows, Britannica will tell you more than World Book, which makes it better for researchers than for elementary schools. I think only time will tell, but there's a lot of expertise out there, and Wickipedia seems to draw unprecedented attention, so it's possible that the two approaches are not mutually exclusive.
I agree that the entries for the popular handles for hybrid orbitals should be kept. I agree that hybridization should be kept as well, but most of the page should be moved to molecular orbitals. There is plenty of complementary material, and we could try to edit the bulk of the article starting with that configuration.
Hybridization is, specifically, the 'mixing' of atomic orbitals into molecular ones. The current hybridization article does a good job of explaining that molecular symmetry is difficult to reconcile with atomic orbitals. I would add (I propose to add!) that the quantum indistinguishability of the groups surrounding the carbon atoms are the source of MO symmetries. To satisfy these necessary symmetries (described by group operations, connecting to group theory), the atomic orbitals are hybridized. The actual hybridization is represented by a linear combination, or superposition of atomic orbitals.
So I like the idea of the hybridization article not defining 'orbital'. By ignoring the actual wave-equation, the article can discuss the geometric implications of hybridizations, which is arguably the 'champion concept' (go Pauling!), without considering things like antibonding orbitals, or the exlusion principle. Definitely keep the methane, although it stinks! ;) rmbh 02:22, Nov 23, 2004 (UTC)
I think the problem with merging the two articles is the approach. Molecular orbitals certainly do lead right into hybridization, but from a very different angle than the one the article currently takes. Merging the introductary material also poses a problem. I'm not sure that they really are cohesive and belong in the same article. We could create two separate articles, "Molecular Orbital approach to Hybridization" and "Atomic Orbital Approach to Hybridization" but that seems unnecessarily extensive. Perhaps the blatantly redundant information could be removed, and a link at the top of the article to molecular orbital saying "A different approach to hybridization can be gleaned from the article on molecular orbitals in lieu of the explanation in terms of atomic orbitals given here." EagleFalconn 03:16, 23 Nov 2004 (UTC)


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)

[edit] revision?

A problem with hybridization is that it is really only used in elementary texts, and this leads to confusion. Thus

  • hybridization has nothing to do with molecular orbitals, but is purely to reconcile the directions of atomic orbitals with molecular shape when used in simple valence bond theory.
  • hybridization using d orbitals is totally discredited, although inertia keeps it in the text books!

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)

Well that is related to what I wanted to ask. I'm certainly not on the level of you guys, but I have skimmed Pauling's book and some other Quantum Chemistry books. Based on what I know, the article seems very wrong in this paragraph:
The answer is the theory of hybridisation. At this time it is important to note that orbitals are, and always will be, a model. They are not real. They are derived from specialised solutions of the Schrödinger equation and therefore to hybridise, to mix an orbital, is simply to change the mathematical function governing where that electron should be. It is not altering the structure of the atom in any way.
Yes they are a model, and have to be, since we can't see the electrons directly. But doesn't this miss the point that the hybridization model is very very satisfactory and predictive for how the structure and reactivity of carbon compounds? Isn't there evidence that the hybridization model is the "right" way to solve the equations for the probabilities of where the electrons are? In other words, isn't it well known that for methane for example, the hybridization model fits very well with what we know to be the forces of the electrons and bonding and the resulting location of the hydrogen atoms? Stating that we are "changing the mathematical function" and "altering the structure" seems to be ignoring that fact. We solve the Schrödinger equation in that way because we believe it fits with observations. And of course it's not altering the structure of the atom. The structure is what it is, we just believe the hybridization modle correctly describes the structure of the molecule. - Taxman Talk 23:59, Jun 9, 2005 (UTC)
Hmm...sort of jumping in here too, so apologies if I've misinterpreted the question. The concept of hybridization in my opinion is exceptionally good for organic chemistry. However, for other other areas, say transition metal chemistry, hybridization isn't nearly so good (in fact it is rather poor). You'd need a lot more sophisticated concepts to deal with it. Nevertheless, hybridization can be cast into a set of heuristics that are very useful for chemistry. I'm not sure what the paragraph refers to when it says "altering the structure...", but I think this has to do with the assumption that each atom (or molecule for that matter) can be approximated as a linear combination of atomic orbitals (LCAO). This explains why hybridization is good for organic chemistry. One is only dealing with "light atoms", as opposed to "heavy atoms" where this assumption does not hold anymore. Furthermore, simple schemes of hybridiziation assume we are using atomic orbitals from hydrogen atoms, since this is the only atom for which we can actually compute analytically their wavefunctions! So in fact, a number of simplification methods are being used here, and they are at best an extremely good heuristic. Hybridization does not have nearly as much predictive power as one would like unfortunately. --HappyCamper 15:24, 30 July 2005 (UTC)
No, I think you've answered it pretty well, but then it seems that the article is in error in the points I pointed out, if only because it does not make the distinction you make between large and small. I don't think I have the expertise to correct that paragraph and not add worse errors. If you could, that would be great. - Taxman Talk 15:48, July 30, 2005 (UTC)
Hmm...I made some changes to the page, but later I might change it again when I get the chance. I think I introduced quite a number of loopholes into the article now. At least it was a good attempt at fixing it up! I just realized that these chemistry related pages need a lot of work. There is so much content that is missing, fundamental concepts which really should be part of this encyclopedia, I think. Can't wait until the end of August when I've got more time to play on Wikipedia... --HappyCamper 16:56, 30 July 2005 (UTC)
*gasp* Wikipedia doesn't even have an article on LCAO?! Too many articles to write, too little time...no wonder why we need "Wikipediholics Anonymous"! --HappyCamper 15:24, 30 July 2005 (UTC)
Actually, we have an article at Linear combination of atomic orbitals molecular orbital method, so I redirected LCAO there. I hope that is correct. - Taxman Talk 16:37, August 1, 2005 (UTC)
Well, it's not quite precise, but I guess it will do. I was thinking that LCAO should only talk about what LCAOs actually are, instead of describing an application of them. When I get the time I'll fix it up. This is too interesting...the reference text in that article I actually have!! --HappyCamper 17:21, 1 August 2005 (UTC)
Ok, then. One week of Wikigulag for you to fix up all of these issues! :) - Taxman Talk 17:50, August 1, 2005 (UTC)
Another issue I had with this article is the hybridization for hypervalent molecules. The theory that d orbitals play a role in hybrid molecular orbitals is obsolete due to the high energy difference between d and p orbitals. A new theory states that a molecule like Phosphorous V Chloride has sp2 hybridization (with one shared resonance p orbital) and Sulfur VI Fluoride has a sp hybridization (with two shared resonance p orbitals). This is still debated among chemists but the new theory is more plausible in light of energy differences. --Falconer Talk 01:23, November 8, 2005 (UTC)

[edit] Spelling

I prefer using "hybridization" rather than "hybridisation". --HappyCamper 15:25, 30 July 2005 (UTC)

Well in general if it is a difference between the British English and the American, policy is not to change from one to another once it is set. But from the above conversations it looks like it is spelled with a 'z' in both, so why is it 's' at all? - Taxman Talk 15:48, July 30, 2005 (UTC)
Yeah, I know...odd isn't it? Well, I habitually spell with "z", but if the article insists on "s", then hopefully my nimble fingers will remember that when I edit :) --HappyCamper 16:36, 30 July 2005 (UTC)
What I was saying is that if everyone agrees 'z' is the more common spelling and it is not a case where British Enlgish uses an 's', this is a case where we should move the article. - Taxman Talk 18:04, August 1, 2005 (UTC)
But it isn't. Hybridisation and hybridise are just like any other words ending in -isation/-ise in British English. Just like realise/realisation or organise/organisation. So they aren't exceptions in British English at all. What I think might have been meant above is that such words are on the rare occasion spelt with a zed in British English because the Oxford English Dictionary prefers -ize/-ization on some etymological grounds, but this is ever more seldom encountered in Britain (and perhaps it is even rarer in countries such as Australia and New Zealand). All British newspapers to the best of my knowledge, for example, use s forms; and in fact, most Britons would find it oddly American to use -ize, even if it was in the past used by perfectly good English writers. See this and this Wikipedia page for some detail.
My books, both textbooks for school/sixth-form as well as the ones used at university, certainly speak of hybridisation (except for the odd one which wasn't written in Britain!). It's definitely and by far the commonest spelling in Britain, so I reckon this article should stay where it is. 213.143.80.81 05:30, 2 August 2005 (UTC)
Ah very well then. In that case, the policy is clear: we leave the spelling where it is. I just misinterpreted what was above I guess. - Taxman Talk 05:43, August 2, 2005 (UTC)
I don't believe hybridise is a word in UK English or US English. I am unable to find a real dictionary that has a definition for Hybridise, though I don't have a subscription to OED to check it for sure, I have checked other dictionaries that usually have both spellings and they all have Hybridize but no "ise" version. - Pete Davis 14:12, July 18, 2006 (UTC)

[edit] Diagram

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)

[edit] Carbon bonds

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)

Always is a dangerous word. Carbon doesn't always form four bonds, but if it can its significantly more stable for it to do, and if the activation energy is low enough and if the process is exothermic enough (ie, enough to prevent simple reconversion to some other bonding state) it will. There are exceptions. Lone carbon atoms, certain reaction intermediates, carbocations. EagleFalconn 07:25, 6 January 2006 (UTC)

[edit] Limited usage to certain groups?

I removed this from the introductory paragraph:

... made of atoms of the groups 2,3,4 of the periodic families of elements. On the other hand, groups 1,5,6 and 7 in the periodic table do not hybridise, i.e. this approach is in that case not useful.

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)

It's been tagged as needing verification and sources; hopefully the original main authors will provide the sources, but it might need to be combed through anyway. --AySz88^-^ 19:24, 4 February 2006 (UTC)
Is this where the dispute is? To fix this article, I think it is important to nail what exactly it should be talking about. I think it would be more valuable to focus on the heurstic aspects of the theory first, and if we have time, add some results about ab initio calculations. --HappyCamper 04:12, 13 May 2006 (UTC)

[edit] Hmm....

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)

Dear HappyCamper, I would like to know what you mean with the remarks in this section. The problem is, I have a similar feeling about this article .. when reading this I get the feeling that people are led to believe that hybridisation really exists. Now I do understand that it is difficult to understand the bonding in methane, when the 3 p-orbitals are pointing in 6 directions, while there are (in general) only 4 atoms around C. It is a very useful concept, but not 'the truth' (if that exists, orbitals are already a concept .. etc. etc.)
By the way, since this evening, Tanabe-Sugano diagrams is not a redlink anymore, though the page contains hardly any info, I just hope that some spectroscopist will really kickstart the page (not my specialisation), it is IMHO really missing. --Dirk Beetstra 20:32, 22 May 2006 (UTC)

[edit] Hybridization theory has been superceded by MO theory?

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)

Hi V8rik, I figured that you would have useful suggestions. My goal was a short "disclaimer" early in the article to prevent impressionable readers believing hybrid orbitals (not that I so much of a theorist to strongly complain, but hybrids have just disappeared from modern textbooks). But I will follow your recommendation to move the section lower down. About getting a photo-electron spectrum on the MO or methane page, that would be desirable, but I dont know where to look for a copyright-ok spectrum. I have ppt slides of qualitative MO's for methane and one of these days I will figure out how to load graphics on WE. --Smokefoot 16:41, 16 September 2006 (UTC)
  • Hi Smokefoot, Thanks for your consideration. Finding spectra for insertion into Wiki is always a problem but I will add some external links to spectra later this evening and some related text. I will also will be happy to collaborate on a MO diagram article, I really think Wiki needs one V8rik 16:50, 16 September 2006 (UTC)
this is the kind of material I have: one of three degenerate components of the bonding T MO for methane.

(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 (CH4MO) 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)

  • that is already more advanced than what I had in mind: something like Link. there exists a nice but peculiar way to save images from chemdraw, summarised here: [1], it will make the images very sharp. V8rik 20:09, 16 September 2006 (UTC)


  • Hi Smokefoot, I have researched some recent general organic chemistry textbooks and I must conclude that hybridization theory is very much alive as far as organic chemists are concerned. I took the liberty to rephrase the paragraph header and added my findings. V8rik 22:05, 29 September 2006 (UTC)
V8rik yes, the organickers love hybridization. And its seems unlikely that this terminology will slip soon. --Smokefoot 22:21, 29 September 2006 (UTC)

[edit] Spelling

(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.—The preceding unsigned comment was added by 70.243.254.146 (talk • contribs).

I am sorry, the original page was written in UK EN, hence name 'orbital hybridisation', and the use of the UK spelling 'hybridisation' throughout the article. People searching for 'orbital hybridization' will be redirected to this page, so they still can find it. Hope this explains. --Dirk Beetstra T C 08:47, 12 December 2006 (UTC)

[edit] valence shell electron-pair repulsion (VSEPR) theory

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)

[edit] Redundant sp2 bond article

(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)

I agree. Put merge tags on the two articles to draw attention to your suggestion. --Bduke 23:20, 27 December 2006 (UTC)
  • support merge V8rik 20:31, 29 December 2006 (UTC)
  • support merge --Dirk Beetstra T C 13:18, 6 January 2007 (UTC)
Done. Itub 16:22, 11 January 2007 (UTC)

[edit] PCl5: why sp3d but s2p3?

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)

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