Several (Gd1−xNdx)2[C2O4]3·nH2O samples (0≤x≤1) were prepared by a coprecipitation method: the precipitation is quantitative and all the samples are homogeneous in stoichiometry.
XRD analyses have shown that a complete solid solution is formed over the whole range of compositions. The dried Gd rich oxalates
have initially a low water content which gradually increases with the Nd content. All the oxalates decompose in O2 around 700°C either into a single mixed oxide or in a mixture of oxides through several steps, which can be ascribed to the
loss of water and CO2.