Identification of binary compounds in the system Ce 2O 3WO 3

Abstract

The systems CeO 2Ce 2O 3WO 3 and Ce 2O 3WO 3W are studied at high temperature. Six compounds were found as stable phases in the system Ce 2O 3WO 3. The compound 3Ce 2O 3 · WO 3 has a fluoritelike cubic structure of a 0 = 11.040 Å and forms solid solutions with constituent oxides or CeO 2. The compound 3Ce 2O 3 · 2WO 3, which seems to be isostructural with 3La 2O 3 · 2WO 3, is stable only in the temperature range, 1545 ∼ 1730°C. The compound Ce 2O 3 · WO 3, which has a monoclinic structure, transforms reversibly at 1360°C to a tetragonal structure with the cell parameters a 0 = 5.469 Å, c 0 = 8.790 Å. The compound Ce 2O 3 · 2WO 3 identified to be monoclinic, also has a reversible transformation at 1105°C. Its high-temperature phase has a cubic cell with the cell parameter a = 7.046 Å. As is well known, Ce 2O 3 · 3WO 3 appeared to have similar high-temperature behavior to La 2O 3 · 3WO 3. The compound 2Ce 2O 3 · 9WO 3, whose structure could not be analyzed, melts congruently at 1026°C.