Relationship of crystal structures to interionic interactions in mono-, di-, tri- and ter-valent metal oxides

Abstract

The ability of an extended ionic interaction model to account for the observed crystal structures of a very wide range of binary oxides is assessed. The model includes the many-body effects which result from ionic polarization and their changes in effective size and shape of ions in different coordination environments. Starting from potentials which have been fully obtained for certain substances on the basis of electronic structure calculations, systematic modifications in the values of key parameters (such as ionic radii) are made, so as to derive potentials for other substances on the basis of an assumed transferability of an ionic interaction model. Comparison of the predicted structures with observation enables the identification of the key parameters which control the evolution of structure type and the physical nature of the interactions responsible for the adoption of ‘covalent’ structures by some materials.