Ligand field theory - Revision history

Apm: /* How it works */ more cleanup

2025-06-29T13:27:41Z

How it works: more cleanup

← Older revision		Revision as of 15:27, 29 June 2025
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	oversimplified: blue side absorption red side looking material <br>		oversimplified: blue side absorption red side looking material <br>
	cleaner but lower signal ESR spectra		cleaner but lower signal ESR spectra

			'''Influenced properties:'''
			* electron configuration and thus
			* magnetic behavior: diamagnetic (all electrons paired) / paramagnetic (& how many unpaired)
			* frequency (sometimes color) of absorbed light

	'''Influencing factors:'''		'''Influencing factors:'''
	* strength of ligand due to chemical identity <br>(O,S,halogen, … weaker; C,N,P, … stronger)		* strength of ligand due to chemical identity <br>(O,S,halogen, … weaker; C,N,P, … stronger)
	* oxidation state		* oxidation state
	* coordination number		* coordination number and coordination geometry <br>tetrahedral => ligands between orbitals => weak field => high spin tendentially <br>square planar coordination: d<sub>x²-y²</sub> > d<sub>z²</sub> > d<sub>xy</sub> > (d<sub>yz</sub> & d<sub>zx</sub>)
	* coordination geometry <br>tetrahedral => ligands between orbitals => weak field => high spin tendentially <br>square planar coordination: d<sub>x²-y²</sub> > d<sub>z²</sub> > d<sub>xy</sub> > (d<sub>yz</sub> & d<sub>zx</sub>)
	* electron configuration

	== spectrochemical series ==		== spectrochemical series ==

Apm: /* How it works */ splitting energy => crystal field splitting ebergy

2025-06-29T13:19:49Z

How it works: splitting energy => crystal field splitting ebergy

← Older revision		Revision as of 15:19, 29 June 2025
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	Octahedral coordination:		Octahedral coordination:
	energy of an electron in e<sub>g</sub> > energy of an electron in t<sub>2g</sub> <br>		energy of an electron in e<sub>g</sub> > energy of an electron in t<sub>2g</sub> <br>
	Tetrahedral coodination: '''~~Splitting~~ energy''': vice versa.		Tetrahedral coodination: '''crystal field splitting energy''': vice versa.

	Octahedral splitting energy … energy of e<sub>g</sub> electron minus energy of t<sub>2g</sub> electron<br>		Octahedral splitting energy … energy of e<sub>g</sub> electron minus energy of t<sub>2g</sub> electron<br>

Apm: /* How it works */

2025-06-29T13:18:50Z

How it works

← Older revision		Revision as of 15:18, 29 June 2025
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	* strength of ligand due to chemical identity <br>(O,S,halogen, … weaker; C,N,P, … stronger)		* strength of ligand due to chemical identity <br>(O,S,halogen, … weaker; C,N,P, … stronger)
	* oxidation state		* oxidation state
	* coordination number <br>tetrahedral => ligands between orbitals => weak field => high spin tendentially <br>square planar coordination: d<sub>x²-y²</sub> > d<sub>z²</sub> > d<sub>xy</sub> > (d<sub>yz</sub> & d<sub>zx</sub>)		* coordination number
			* coordination geometry <br>tetrahedral => ligands between orbitals => weak field => high spin tendentially <br>square planar coordination: d<sub>x²-y²</sub> > d<sub>z²</sub> > d<sub>xy</sub> > (d<sub>yz</sub> & d<sub>zx</sub>)
	* electron configuration		* electron configuration
	* coordination geometry

	== spectrochemical series ==		== spectrochemical series ==

Apm: /* How it works */

2025-06-29T13:18:02Z

How it works

← Older revision		Revision as of 15:18, 29 June 2025
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	'''Influencing factors:'''		'''Influencing factors:'''
			* strength of ligand due to chemical identity <br>(O,S,halogen, … weaker; C,N,P, … stronger)
	* oxidation state		* oxidation state
	* coordination number <br>tetrahedral => ligands between orbitals => weak field => high spin tendentially <br>square planar coordination: d<sub>x²-y²</sub> > d<sub>z²</sub> > d<sub>xy</sub> > (d<sub>yz</sub> & d<sub>zx</sub>)		* coordination number <br>tetrahedral => ligands between orbitals => weak field => high spin tendentially <br>square planar coordination: d<sub>x²-y²</sub> > d<sub>z²</sub> > d<sub>xy</sub> > (d<sub>yz</sub> & d<sub>zx</sub>)
	* electron configuration		* electron configuration
	* coordination geometry		* coordination geometry
	* strength of ligand due to chemical identity (O,S,halogen, … weaker; C,N,P, … stronger)

	== spectrochemical series ==		== spectrochemical series ==

Apm: /* How it works */

2025-06-29T13:17:18Z

How it works

← Older revision		Revision as of 15:17, 29 June 2025
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	* electron configuration		* electron configuration
	* coordination geometry		* coordination geometry
	* chemical identity ~~of the ligands~~ (O,S,halogen, … weaker; C,N,P, … stronger)		* strength of ligand due to chemical identity (O,S,halogen, … weaker; C,N,P, … stronger)

	== spectrochemical series ==		== spectrochemical series ==

Apm: /* How it works */ fixed typo & added mention of square planar coordination case

2025-06-29T13:16:02Z

How it works: fixed typo & added mention of square planar coordination case

← Older revision		Revision as of 15:16, 29 June 2025
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	* electrons in t<sub>2g</sub> block don't get paired up before moving up to the higher energy e<sub>g</sub> block (i.e. Hund's rule for all d orbitals)<br>		* electrons in t<sub>2g</sub> block don't get paired up before moving up to the higher energy e<sub>g</sub> block (i.e. Hund's rule for all d orbitals)<br>
	'''=> high spin complex''' <br>		'''=> high spin complex''' <br>
	oversimplified: red side ~~absorbtion~~ blue side looking material <br>		oversimplified: red side absorption blue side looking material <br>
	more complex but higher signal ESR spectra (spin-spin coupling between multiple unpaired electrons).		more complex but higher signal ESR spectra (spin-spin coupling between multiple unpaired electrons).

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	– all electrons in t<sub>2g</sub> do get paired up before moving up to the higher energy e<sub>g</sub> block <br>		– all electrons in t<sub>2g</sub> do get paired up before moving up to the higher energy e<sub>g</sub> block <br>
	'''=> low spin complex'''		'''=> low spin complex'''
	oversimplified: blue side ~~absorbtion~~ red side looking material <br>		oversimplified: blue side absorption red side looking material <br>
	cleaner but lower signal ESR spectra		cleaner but lower signal ESR spectra

	'''Influencing factors:'''		'''Influencing factors:'''
	* oxidation state		* oxidation state
	* coordination number (tetrahedral => between orbitals => weak field => high spin tendentially)		* coordination number <br>tetrahedral => ligands between orbitals => weak field => high spin tendentially <br>square planar coordination: d<sub>x²-y²</sub> > d<sub>z²</sub> > d<sub>xy</sub> > (d<sub>yz</sub> & d<sub>zx</sub>)
	* electron configuration		* electron configuration
	* coordination geometry		* coordination geometry

Apm: /* How it works */ some inprovements

2025-06-29T13:10:34Z

How it works: some inprovements

← Older revision		Revision as of 15:10, 29 June 2025
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	Smaller orbital => electrons closer together => higher electron pairing energy => high spin more likely		Smaller orbital => electrons closer together => higher electron pairing energy => high spin more likely

	The 8 electron d-orbital-block (block … same energy electron states) <br>		The eight electron d-orbital-block (block … same energy electron states) <br>
	due to interaction in the crystal gets split up into two blocks		due to interaction in the crystal gets split up into two blocks
	* the t<sub>2g</sub> 6 electron block		* the t<sub>2g</sub> six electron block (d<sub>xy</sub>, d<sub>yz</sub>, d<sub>zy</sub>)
	* the e<sub>g</sub> 2 electron block		* the e<sub>g</sub> two electron block (d<sub>x²-y²</sub>, d<sub>z²</sub>)
	~~Energy~~ of an electron in e<sub>g</sub> ~~minus <br~~>
	energy of an electron in t<sub>2g</sub> <br>		Octahedral coordination:
	~~is the~~ '''~~octahedral splitting~~ energy'''. <br>		energy of an electron in e<sub>g</sub> > energy of an electron in t<sub>2g</sub> <br>
			Tetrahedral coodination: '''Splitting energy''': vice versa.

			Octahedral splitting energy … energy of e<sub>g</sub> electron minus energy of t<sub>2g</sub> electron<br>
	LCOAO-energies … linear combination of atomic orbitals <br>		LCOAO-energies … linear combination of atomic orbitals <br>
	ESR … electron spin resonance <br>		ESR … electron spin resonance <br>
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	'''Weak field ligand and/or smaller metal orbital''' <br>		'''Weak field ligand and/or smaller metal orbital''' <br>
	Octahedral splitting energy < total electron pairing energy <br>		Octahedral splitting energy < total electron pairing energy <br>
	– e<sub>g</sub> block starts filling before any electrons occupy t<sub>2g</sub> is fully occupied		* e<sub>g</sub> block starts filling before any electrons occupy t<sub>2g</sub> is fully occupied
	– electrons in t<sub>2g</sub> don't get paired up before moving up to the higher energy e<sub>g</sub> block (i.e. Hund's rule for all d orbitals)<br>		* electrons in t<sub>2g</sub> block don't get paired up before moving up to the higher energy e<sub>g</sub> block (i.e. Hund's rule for all d orbitals)<br>
	'''=> high spin complex''' <br>		'''=> high spin complex''' <br>
	oversimplified: red side absorbtion blue side looking material <br>		oversimplified: red side absorbtion blue side looking material <br>
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	'''Influencing factors:'''		'''Influencing factors:'''
	* oxidation state		* oxidation state
	* coordination number		* coordination number (tetrahedral => between orbitals => weak field => high spin tendentially)
	* electron configuration		* electron configuration
	* coordination geometry		* coordination geometry

Apm: /* External links */ added link to relevant explanatory video

2025-06-29T12:28:43Z

External links: added link to relevant explanatory video

← Older revision		Revision as of 14:28, 29 June 2025
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	{{wikitodo\|there are some quite good video series on ligand field theory on youtube - add links to those}}		{{wikitodo\|there are some quite good video series on ligand field theory on youtube - add links to those}}

			Video: [https://www.youtube.com/watch?v=8lT21wKoXyQ Professor Dave Explains – Crystal Field Theory]

Apm: /* Related */

2025-06-28T12:20:36Z

← Older revision		Revision as of 14:20, 28 June 2025
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	* '''[[Color center]]s'''		* '''[[Color center]]s'''
	* [[Atomic orbitals]]		* [[Atomic orbitals]]
	* [[Fun with spins]]		* '''[[Fun with spins]]'''
	* [[Electronic transitions]] – [[Inter system crossing]]		* [[Electronic transitions]] – [[Inter system crossing]]
	----		----

Apm: /* How it works */

2025-06-28T11:48:20Z

How it works

← Older revision		Revision as of 13:48, 28 June 2025
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	– all electrons in t<sub>2g</sub> do get paired up before moving up to the higher energy e<sub>g</sub> block <br>		– all electrons in t<sub>2g</sub> do get paired up before moving up to the higher energy e<sub>g</sub> block <br>
	'''=> low spin complex'''		'''=> low spin complex'''
	oversimplified: blue side absorbtion red side looking material		oversimplified: blue side absorbtion red side looking material <br>
	cleaner but lower signal ESR spectra		cleaner but lower signal ESR spectra