Effect of temperature and pressure on mixed oxide solid solutions

A hydrothermal synthesis of ZrW2-xMoxO8 (0≤x≤2) from the corresponding precursors is reported in this paper. High- temperature and high-pressure data are presented for the sample with x=1.6. An increase in temperature initiates the phase transition from tetragonal precursor to orthorhombic-ZrW2-xMoxO8 (x=1.6) with the subsequent formation of cubic and trigonal phases. The thermolysis parameter of the disordered cubic ZrW2-xMoxO8 (x=1.6) phase is 803 K, and the coefficient of thermal expansion is α= -4.6∙10–6 K–1. Data on ZrW2-xMoxO8 (x=1.6) structure as a function of pressure are obtained for the first time. Pressure-induced changes from cubic to orthorhombic ZrW2-xMoxO8 (x=1.6) phase at 1.38 GPa are observed. The sample amorphization is irreversible during decompression.