Anomalous thermal expansion of osmium dioxide

Abstract

AbstractThe precision lattice parameters of osmium dioxide have been determined at different temperatures, in the temperature range 30–444 °C, using a Unicam high temperature powder camera 19 cm in diameter and CuKα radiation. The data have been used to evaluate the coefficients of thermal expansion at various temperatures by a graphical method. The ‘a’ parameter increases non‐linearly with increasing temperature while the ‘c’ parameter remains constant throughout the range of temperature studied indicating a zero coefficient of expansion along the c‐direction. The abnormal thermal behaviour of this compound is explained in terms of the electronic configuration of the d‐shell of the cation.