Question

In which case Jahn Teller effect is maximum?
A.${{d}^{3}}$
B.${{d}^{8}}$
C.${{d}^{9}}$
D.${{d}^{10}}$

Answer 1

The Jahn Teller effect, which is also known as Jahn Teller distortion, helps to describe the geometry, distortion of molecules and ions, which result from certain electronic configuration. It is used to determine the structure of transition metal complexes.

Complete step by step answer:
In this effect, all the nonlinear molecules that have degenerated electronic ground state will show some geometrical distortion and removal of degeneracy takes place. Mostly, Jahn Teller effect if found in octahedral complexes. This effect is used to determine the structure of transition metal complexes.
As we know, the Jahn Teller effect is related to UV absorbance spectra, the Jahn Teller effect is maximum when the electrons are unpaired. Therefore, ${{d}^{3}}$ is the only orbital that has three single electrons and hence the Jahn Teller effect increases.
The UV radiation absorbance causes the splitting of bands.
Therefore, the correct option is (A) ${{d}^{3}}$ .

Additional information:
-If the concentration is high of electron density associated with degenerate orbitals then the Jahn Teller effect is also stronger. Hence, it plays a major role in determining the structure of transition metal complexes.
-The Jahn Teller effect is stronger in case of $Cu(II)$
-Antibonding sigma character is strongly displayed by degenerate orbitals.
-Copper is considered as a transition metal that shows strong electron affinity and yields more covalent bonds than other metals that increase the Jahn Teller linear coupling constant.

Note: In the conclusion, we have seen that the maximum number of unpaired electrons will show maximum Jahn Teller effect. In this question only ${{d}^{3}}$ shows unpaired electrons all the other options have paired electrons that is why the correct option is ${{d}^{3}}$ .