Synthesis, Structure, and Thermophysical Properties of EuGaGe2O7

The europium gallium germanate EuGaGe 2 O 7 has been prepared by solid-state reaction in air in the temperature range 1273–1473 K using a stoichiometric mixture of Eu 2 O 3 , Ga 2 O 3 , and GeO 2 . Its crystal structure has been determined by X-ray diffraction (sp. gr. P 2 1 / c , a = 7.1693(7) Å, b = 6.57008(6) Å, c = 12.7699(1) Å, β = 117.4522(5)°, V = 533.768(8) Å 3 ). The heat capacity of polycrystalline samples has been determined by differential scanning calorimetry in the temperature range 350–1053 K and the experimental data have been used to calculate the thermodynamic properties (enthalpy increment, entropy change, and reduced Gibbs energy change) of EuGaGe 2 O 7 .