Thermal expansion studies of Gd2Mo3O12 and Gd2W3O12

Simultaneous thermogravimetric/differential thermal analysis of Gd2Mo3O12 showed an irreversible phase transition at 1178 K where as Gd2W3O12 showed reversible phase transition at 1433 K, which were confirmed by powder X-ray diffraction. The thermal expansion behavior of α-Gd2Mo3O12 (room temperature phase), β-Gd2Mo3O12 (phase obtained by heating Gd2Mo3O12 at 1223 K) and Gd2W3O12 have been investigated using high temperature X-ray diffractometer. The cell volume of α-Gd2Mo3O12, β-Gd2Mo3O12 and Gd2W3O12, fit into polynomial expression with respect to temperature, showed positive thermal expansion up to 1073, 1173 and 1173 K, respectively. The average volume expansion coefficients for α-Gd2Mo3O12, β-Gd2Mo3O12 and Gd2W3O12 are 39.52 × 10−6, 21.23 × 10−6 and 37.96 × 10−6 K−1, respectively.