Structure and thermodynamic properties of the SmGaGe$_{2}$O$_{7}$ oxide

The SmGaGe$_{2}$O$_{7}$ oxide material has been obtained from initial Sm$_{2}$O$_{3}$, Ga$_{2}$O$_{3}$, and GeO$_{2}$ oxides by solid-phase synthesis with annealing in air in the temperature range of 1273–1473 K. The structure of the investigated germanate (sp. gr. $P$2$_1/c$, $a$ = 7.18610(9) $\mathring{\mathrm{A}}$, $b$ = 6.57935(8) $\mathring{\mathrm{A}}$, and $c$ = 12.7932(2) $\mathring{\mathrm{A}}$) has been established by X-ray diffraction and the high-temperature heat capacity has been determined by differential scanning calorimetry. Using the experimental data on $C_p = f(T)$, the thermodynamic properties of the compound have been calculated.