Abstract
A disorder phase with a cubic pyrochlore lattice (space group Fa3m) was obtained by rapid quenching of a Gd3TaO7 (3Gd2O3⋅Ta2O5) melt. A fluorite-related phase with orthorhombic weberite lattice (C2221) was formed both by firing at 1350°C for 96h or at 1700°C for 4h, and by melting of the 3Gd2O3+Ta2O5 mixture. Annealing at 1350°C for 96h or at 1700°C for 4h of the rapidly quenched pyrochlore also produced the weberite phase. Order-disorder transition may occur above 1700°C in this compound.
