High-temperature specific heat of Bi$_{2}$GeO$_{5}$ and SmBiGeO$_{5}$

The SmBiGeO$_{5}$ compound is synthesized from Sm$_{2}$O$_{3}$, Bi$_{2}$O$_{3}$, and GeO$_{2}$ by solid-state synthesis with subsequent annealing at 1003, 1073, 1123, 1143, 1173, and 1223 K. The metastable Bi$_{2}$GeO$_{5}$ compound is prepared from melt. Temperature dependences of specific heat of Bi$_{2}$GeO$_{5}$ (350–1000 K) and SmBiGeO$_{5}$ (370–1000 K) are measured by differential scanning calorimetry. Basing on the experimental dependences $C_P = f(T)$, the thermodynamic functions of the oxide compounds are calculated.