so their σ-symmetrical orbitals form bonding orbitals with the dz2 and dx2-y2 orbitals.
Is the hyphen in the subscript above supposed to be a minus sign? If so, it should say
since the stubby little hyphen is hard to see. Michael Hardy 18:09, 10 May 2005 (UTC)
I noticed this a little late (I'm not a faithful pagewatcher I must admit) but you are right. I changed the hyphen into a minus sign and will continue to use the minus sign if I get to expansion of this article. Thanks!
-- tijmz 4 July 2005 14:28 (UTC)
Can I just say that this is a really good explanation of ligand field theory given that there are no diagrams! Well done, whoever wrote most of it (although the last section isn't quite so good - I might have a crack at that later).-- Brichcja 18:25, 24 May 2006 (UTC)
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I feel the last section, on LFSE, is very confusing. Furthermore, I think it's wrong. What is described here is Crystal Field Stabilisation Energy (CFSE), because it is assuming that the Barycentre rule applies: (i.e. that the t2g go down by 2/5 Δo and the eg go up by 3/5 Δo). If you look at the MO diagram, this plainly isn't true beacuse the t2g are often non-bonding (they don't go down at all), and if they do go down, the amount is not related to how far the eg have gone up, it's related to the amount of π-bonding.
Any thoughts?
Chris 21:30, 26 December 2006 (UTC)
OK, I removed the LFSE section for the reasons given above. I wrote a section on CFSE and put it on the crystal field theory page to replace it. Chris 19:50, 31 December 2006 (UTC)
I added some stuff about the spectrochemical series, because LFT explains it and the spectrochemical series is empirical evidence for LFT. There is a page for the spectrochemical series, but it doesn't really say anything other than give the same list of ligands. There's no explanation there for it, and I would be tempted to blank it and turn it into a redirect to here. Equally, there's a bit on the spectrochemical series on the CFT page, which I am going to remove. It's got nothing to doo with CFT, and everything to do with LFT.... Chris 22:12, 31 December 2006 (UTC)
What in the world does this sentence mean in the first paragraph:
For first row transition metals, n = 3; for second and third row metals, n = 4 and 5, respectively.
OK - now I see that these are the principal quantum numbers - well that wasn't at all clear, so I am rewriting this sentence.
As I read further, there are a lot of unexplained or outright unclear sections in this article. In the figure, for example, what is "M-L sigma"??? I suspect what is going on is d2sp3 hybridization, with a single electron remaining in the 3 unhybridized orbitals, but I'm reading this because I really don't know this subject, so someone else had better undertake the rewriting.
A day later ...
Hey Brichcja! I understand what you saw a need to correct, but you don't define "n" at any point, and what the heck are "five nd"??? The following sentence in the version you just created just makes no sense:
"A transition metal ion has nine atomic orbitals of appropriate energy to engage its ligands, which are five nd, one (n+1)s, and three (n+1)p orbitals. For first row transition metals, n = 3; for second and third row metals, n = 4 and 5, respectively." —Preceding unsigned comment added by 67.190.157.17 ( talk) 01:20, 9 January 2009 (UTC)
Everything under the main title LFT is properly described as MO theory of transition-metal complexes. LFT is a FIELD theory (like Crystal-field theory). It seeks (pretty successfully) to represent certain TM properties by a pseudo-potential approach in which the environment of the TM ion/atom by an effective ONE-electron operator (a potential). Mo theory does no such thing but is a many-electron theory. MO theory and field theories are like chalk and cheese. This is not an academic point but a crucial point which was very well understood all those years ago by Van Vleck. Unfortunately, he has been little read on this issue and frequently misunderstood.
I'm afraid, therefore, that Wikipedia's whole entry for Ligand-field theory is just silly. —Preceding unsigned comment added by Gerloch ( talk • contribs) 09:42, 9 February 2009 (UTC)
Well, I'm sorry. I should have added that LFT involves a one-electron operator acting within a PURE d or f electron basis. So, within applications to the d block, calculations explicitly make no mention of orbitals (one-electron wavefunctions) other than d. Furthermore, no mention is made of the radial part of those d functions for that is wrapped up in the LF parameters. It is simply not possible to calculate such radial functions without enormously difficult computations of an entirely different sort and those are not especially successful anyway.
As to your other point about sticking to 'conventional wisdom' (my words, I admit): why bother if that old-fashioned wisdom is simply wrong? It would be nice if this new medium (Wikipedia) could provide something more up to date and correct than that of the past 40 years. Anyway, I'm off! —Preceding unsigned comment added by Gerloch ( talk • contribs) 07:30, 4 March 2009 (UTC)