In the system ZrO2-CeO2, metastable t-ZrO2 solid solutions containing up to 30 mol % CeO2 crystallize at temperatures of 385-430 degrees C from amorphous materials prepared by the hydrazine method. Crystalline Ce3ZrO8 solid solutions are formed in as-prepared powders between 30-75 mol % CeO2. The variation of the lattice parameters of both solid solutions is determined as a function of CeO2 content. The value of the lattice parameter of pure Ce3ZrO8 (cubic) is a = 0.5342 nm. Detailed characterization of the Ce3ZrO8 powder has been performed. Crystallite size and particle size are strongly dependent on the heating temperature. Specific surface areas do not drop below 40 m(2) g(-1) until the heating temperature is above 1000 degrees C.