Deformation of the Octahedral Layers in the Delafossite Type Compounds

Abstract

In the delafossite (CuFeO₂) type compounds (A⁺B³⁺O₂), structural variation with B-site ion was studied. The deformation of BO₆ octahedron in the direction of the three-fold axis increased with increasing ionic radius of the B-site ion, r_B. The degree of deformation increased drastically at r_B greater than 0.8-0.9Å. These results were analyzed through the computation of lattice energy. The crystal was assumed basically ionic and the covalency of the A-O-B bonds in the crystal was taken into account.