Talk:Crystal field theory

Splitting diagrams

With respect to the two splitting diagrams shown in the article, I think the t_u orbitals should be labeled e_g instead for an octahedral complex. I have taken the time to modify the diagrams shown and will upload them if any one concurs that it is more correct to label the t_u orbitals as e_g--YanA 06:42, 2 March 2006 (UTC)

Can't see any t_u orbitals here Chris 05:50, 30 August 2006 (UTC)

Yeah, I changed that while ago.--YanA 09:45, 1 November 2006 (UTC)

Rewrite

Had quite a major rewrite, introducing high and low spin section. I propose to move ligand-field stabilisation here as well (and rename it crystal field stabilisation).--Chris 21:11, 24 May 2006 (UTC)

Proposed move

Propose move crystal field splitting to ligand field splitting. — Preceding unsigned comment added by 203.101.233.39 (talk) 23:12, 29 August 2006 (UTC)

Image change

I have changed the old .jpg images to .png images to remove the compression artifacts.--YanA 06:18, 10 November 2006 (UTC)

Explaining the colours of transition metal complexes

I have rewritten this, to make it a bit clearer. However, I feel much of it is misleading and should be removed. It implies that the energy of the photon absorbed is equal to Δ, which is simply not true for d² to d⁹ complexes. These often absorb at two or three different wavelengths, none of which is equal to Δ. What is written here is a gross oversimplification. Thoughts??

OK, nobody said anything so I made a few changes to remove this problem.Chris 17:11, 29 December 2006 (UTC)

Connection with point groups symmetry

Perhaps it would be useful to add that the splitting of orbitals under any type of symmetry can be easily deduced from the character tables (for example for d-orbitals in octahedral symmetry: look up z², x², xy, xz, yz, you will find e_g and t_2g). Though to figure out how the energies of the orbitals relate to one another chemical intuition (for the simple cases) or computation (for the more complicated ones) is required 94.210.104.70 (talk) 13:31, 17 October 2014 (UTC)

CFSE

I wrote a section on CFSE. It could with a diagram to illustrate the 2/5 - 3/5 splittng though, should anybody feel so inclined...Chris 19:47, 31 December 2006 (UTC)

I'll place it on my list of things to do.--YanA 01:45, 29 April 2007 (UTC)

Can u calculate CFSE for square pyramidal complexes. If u can please solve for any d-system. Aejaz Ul Bashir (talk) 18:47, 30 July 2020 (UTC)

Planned Work

• Touching up grammar and content (i.e. more consistent use of Δ with and without subscripts.
• Crystal field splitting diagrams for other geometries (most likely of similar quality to those already there).

I'll get to having most of this done by early June assuming no one objects to my plans or has other suggestions.--YanA 20:23, 30 April 2007 (UTC)

Iron

I don't know who thinks that Fe has 5 d-elektrons, but it has 6.

Um, iron(III) has 5. Chris 19:13, 18 May 2007 (UTC)

Split article?

I'm thinking of creating crystal field stabilization energy as a subarticle of this one...thoughts? --HappyCamper (talk) 23:41, 24 December 2007 (UTC)

Which English?

OK, not trying to start an argument here, but the article needs to be consistent as per WP:MOS. Any of you regulars know who was first and which English (UK or US) the article was started in? We've got both in there (e.g. colour and stabilization). I'm happy to edit it but I'm not about to start a war all over again :) Freestyle-69 (talk) 02:45, 8 April 2008 (UTC)

From looking at past versions of this article, it looks like it was started in American English, but it was transitioned to British English in late 2006 and early 2007.--YanA (talk) 04:10, 26 April 2008 (UTC)

Aha- just made a minor edit and saw this- thanks. I'll put it into US English as per WP:MOS#National varieties of English when I get some time. Cheers, Freestyle-69 (talk) 04:21, 28 April 2008 (UTC)

Spectrochemical series

There are a few compounds that could be accommodated in the Spectrochemical series mentioned in the article. Some of them being EDTA, EtOH, etc. If no one has objections, I'll do the edits in a day or two

Darshit 08:37, 28 February 2010 (UTC)

• Actually, there's a bigger list at Ligands which has these in it.Chris (talk) 08:59, 28 February 2010 (UTC)

Octahedral CFSE diagram

This appears to show a diagram of an insertion reaction instead of the orbital energy levels? Anareon (talk) 16:47, 20 January 2011 (UTC)

Yes, you are correct, thank you. I have traced the problem to the image file File:Octahedral.png which can be seen by clicking on the incorrect diagram. Its File history showed that it contained the correct diagram until edits on 3 Dec 2010 and 14 Dec 2010 which substituted the insertion reaction diagram, apparently for use in the new article Insertion reaction, created 15 Dec 2010. Evidently someone did this without considering the effect on this article, or the articles in other languages which also use the same image file.

What needs to be done is to create two image files: rename ("move") the current Octahedral.png as Insertion.png (or some similar name) for use in the Insertion reaction article, and restore the old version (prior to Dec 2010) of Octahedral.png for use in this article. Does anyone know how to do this? Dirac66 (talk) 23:09, 20 January 2011 (UTC)

Fixed. DS (talk) 04:57, 25 January 2011 (UTC)

Square planar splitting diagram

The square planar splitting diagram is wrong. The dz2 should be a higher energy state than dxy. — Preceding unsigned comment added by Hunterbender (talk • contribs) 14:26, 4 October 2012 (UTC)

I have moved this most recent edit to the end of the talk page. The point is debatable. I have found a diagram in W.L. Jolly, Modern Inorganic Chemistry (McGraw-Hill 1984, p.364) which agrees with the diagram now in the article: in order of increasing energy (dxz, dyz), dz2, dxy, dx2-y2. The text near Jolly's diagram admits that the relative orbital energies depend on quantitative properties of the metal ion and ligands, but adds that the dz2 energy is comparable to (dxz, dyz) for complexes of Co(II), Ni(II) and Cu(II). Dirac66 (talk) 14:05, 5 October 2012 (UTC)

A general comment

There are many weaknesses in this article. I recommend An introduction to transition-metal chemistry, Ligand-Field theory by Leslie E. Orgel, Methuen (1960) for a clear introduction to the topic. Petergans (talk) 10:47, 6 January 2017 (UTC)

I have now added this book to the list for Further reading. Dirac66 (talk) 01:23, 8 January 2017 (UTC)

Crystal field splitting for linear and trigonal complexes

I think this page should include the crystal field splitting for linear and trigonal coordination entities like diamminesilver(I), dicyanidoaurate(I), triiodomercurate(II) etc. Sayan Ghosh 12:56, 11 February 2018 (UTC)

CFT for square pyramidal geomatries

The pattern of splitting is: dx2-y2 dz2 dxy dxz dyz and Crystal field splitting parameter is: D = dxy---->dx2-y2 But i need to know what is the energy of each orbital as per (del)° Aejaz Ul Bashir (talk) 18:45, 30 July 2020 (UTC)

Updating CFT splitting diagrams

I'm considering updating the splitting diagrams that I made 14 years ago. The current ones look pixelated and generally low quality. -- YanA (talk) 11:28, 5 November 2021 (UTC)

d-d transaction

Sanyojkta band siddhant 2409:4052:90B:D511:0:0:E1B:88B1 (talk) 15:45, 11 April 2022 (UTC)

How does repulsion generate an increase in energy?

Hi there,

there's a point that seems unclear to me, in the article as well as in all the courses I found on this topic. The first step of the reasoning for crystal field theory goes like: "if the metal ion is surrounded by a spherical shell of negative charges, the electrostatic repulsion (between the shell and the electrons of the ions) leads to an increase of the orbitals energy". I would expect that the repulsion would generate a decrease in energy: adding an outer negative shell reinforces the electric field oriented from the nucleus to the outside, the electrons are "forced" towards the nucleus and more energy is required to release them (higher binding energy = lower (more negative) energy of the orbital). Can someone clarify this? 87.86.104.114 (talk) 05:52, 15 April 2022 (UTC)

When ligands approach an ion, the electrons already on the ion suffer both repulsion by the ligands and increased attraction by the ionic nucleus, so it is not obvious which is stronger. The book cited by Miessler and Tarr says (p.318) that "The chief drawbacks to the crystal field approach are in its concept of the repulsion of orbitals by the ligands and its lack of any explanation for bonding in coordination complexes. ... any interaction between orbitals leads to both higher- and lower-energy molecular orbitals. The purely electrostatic approach does not allow for the lower (bonding) molecular orbitals, and thus fails to provide a complete picture of the electronic structure. Dirac66 (talk) 21:31, 10 May 2022 (UTC)