Thermal decomposition of mixed Ce and Gd oxalates and thermal properties of mixed Ce and Gd oxides

The aim of the present work is to study the thermal decomposition of the mixed oxalates (Ce_1–xGd_x)₂(C₂O₄)₃·nH₂O. The mechanisms of decomposition of Ce and Gd oxalate are different, and mixed oxalates behave in an intermediate way. Their dehydration stages are more similar to those of Gd oxalate, as not all the molecules of water are equivalent like the cerium oxalate. The decomposition leads to (Ce_1–xGd_x)O_2–x/2. For x close to 0 or to 1 two solid solutions exist, while for the central composition, the presence of a biphasic region can not be excluded.