Elastic Moduli Of Perovskite-type Rare Earth Rhodium Borides And Carbides

In this paper, semi-empirical formula for the bulk modulus (B in GPa) and shear modulus (G in GPa) of perovskite structured solids are elaborated in terms of lattice constant (a in Å) and product of ionic charges (Za Zx) of the bonding. Values of bulk modulus, of the group ARh3X, (X = B and C) perovskite-type materials exhibit a linear relationship when plotted against the lattice constant (a) normalization, but fall on different straight lines according to the product of ionic charges of the compounds. The resulting expressions can be applied to a broad selection of perovskite (ARh3X = A: large cation with different valence and X: borides and carbides) materials and their modulus predictions are in good agreement with the experimental data and those from ab initio calculations.