Electronic configuration of cations in some distorted spinels

Abstract

Two apparently different approaches have been used for explaining the distortion to tetragonal symmetry of some spinels. Both, however, rely on the behaviour of cations having 3d electrons. Thus in one the origin of distortion is attributed to the ability of these cations (for example, Mn³⁺) to form the appropriate covalent bonds with the overlapping oxygen orbitals. On the other hand, the second approach relates it to the crystal field effects and Jahn-Teller distortions4 of ligands around such cations.