RELATION BETWEEN POISSONS RATIO AND IONICITY IN SIMPLE BINARY CUBIC COMPOUNDS

Abstract

The nature of the atomic forces in solids may be obtained from a knowledge of the elastic constants. Covalent compounds have a tetrahedral structure, whereas ionic compounds have a rock salt or caesium chloride structure, and it is necessary that appropriate models should be applied to explain the elastic properties of covalent and ionic crystals because of the difference in the crystal symmetry and bonding character. Elastic properties of covalent and ionic compounds have been explained using a valence-force-field model and deformation dipole model respectively. A more qualitative interpretation concerning the relation between Poisson's ratio and ionicity in simple binary cubic compounds is given in this study.