Investigation of double oxides in the system of Pr2O3-WO3

Powdered samples composed of Pr2O3 and WO3 in various mixing mole ratios we re heat-treated in an air flow or in an N-2 gas flow at 1000 degrees C. The phases formed in the samples were investigated by XRD. Single phases of th e five double oxides of the mole ratios Pr2O3:WO3 of 1:4.4, 1:3, 1:2, 1:1, and 5:2 were obtained at the respective mixing mole ratios by a reaction in air. The single phase of 3:1 oxide, which was reported to be obtained in a vacuum or an Ar atmosphere, was not obtained by a heat treatment in air bu t rather by a reaction in an N-2 atmosphere. Furthermore. the crystal syste m and the lattice parameters were determined for the double oxides with the mole ratios of 1:4.4, 1:3, 1:1, and 5:2. (C) 1999 Elsevier Science S.A. Al l rights reserved.