I've been learning how the Jahn Teller Distortion effects the orbitals in Metal complexes and how the splitting of eg and t2g orbitals happens.
But the book mentions that the effect is strong for electron configurations where the eg orbital has 1 or 3 electrons. I can't figure out what that's the case. Why isn't the effect strong with 2 electrons in the eg orbital as well?
If the orbitals of the metal core is distorted. the amount of splitting is not high enough to promote the pairing of energy. therefore the 2 electrons will go to two separate eg orbitals. let the splitting energy due to this distortion be β1. the electron in the lowers orbital will have an energy loss of β1/2 and the electron in the higher orbital will have an energy gain of β1/2 and therefore the net gain in the energy is 0. which does not give any additional stability to the complex(as there is no release of energy).
hence the distortion does not have a strong effect.
