Substitution reactions of metal complexes with this geometry are governed by the Eigen–Wilkins mechanism. For 10 points each:
[10e] Name this molecular geometry, whose d-orbitals are split into two e-sub-g levels above three t-sub-2g levels in crystal field theory. Copper(II) complexes with this geometry are distorted in a common example of the Jahn–Teller effect.
ANSWER: octahedral
[10m] These diagrams predict EM absorptions for octahedral complexes with d2 to d8 metal ions, with a discontinuity seen from d4 to d7. Both axes on these doubly-eponymous diagrams use the Racah B parameter.
ANSWER: Tanabe–Sugano diagrams [prompt on partial answer; prompt on T–S diagrams]
[10h] Tanabe–Sugano diagrams are used to measure this effect, in which a transition-metal–ligand bond leads to a decrease in the Racah B parameter. This effect governs a namesake series in which iodide has the greatest effect.
ANSWER: nephelauxetic effect [accept nephelauxetic series]
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