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The RGaTi2O7 (R = Sm, Ho, Tm, Yb) substituted titanates have been prepared by solid-state reactions, by firing mixtures of the Ga2O3, TiO2, and R2O3 oxides in air at 1273 and 1573 K, and their crystal structure has been determined using X-ray diffraction. The effect of temperature (320–1000 K) on the heat capacity of the synthesized compounds has been studied by differential scanning calorimetry. The experimental Cp(T) data have been used to calculate the principal thermodynamic functions of the titanates. Using the group contribution method, we evaluated the standard enthalpy and Gibbs energy of formation of the RGaTi2O7 (R = Sm, Ho, Tm, Yb) titanates. [ABSTRACT FROM AUTHOR]

The CaSm2Ge3O10 germanate has been prepared by firing stoichiometric mixtures of CaCO3, Sm2O3, and GeO2 in air in the temperature range 1423–1473 K. X-ray powder diffraction characterization with the use of the derivative difference minimization method has shown that CaSm2Ge3O10 has a monoclinic structure (sp. gr. P21/c, 293 К) with unit-cell parameters a = 6.9779(8) Å, b = 6.92859(7) Å, c = 18.8907(2) Å, and β = 108.3280(8)°. The high-temperature heat capacity of calcium samarium germanate samples has been determined in the temperature range 320–1000 K by differential scanning calorimetry and the experimental Cp(T) data have been used to evaluate thermodynamic properties of CaSm2Ge3O10. [ABSTRACT FROM AUTHOR]

Phase relations in the Ga-Ge-Sb ternary system were investigated experimentally, using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and differential scanning calorimetry (DSC). Nine ternary samples were prepared by melting of pure elements under an argon atmosphere. The compositions of the prepared alloys were situated along three cross sections with the molar ratios Ga:Ge = 1, Ga:Sb = 1 and Ge:Sb = 1. Phase transition temperatures of the investigated samples were determined using DSC. The microstructure of the samples was analyzed using a scanning electron microscope with EDS and co-existing phases were identified. Binary thermodynamic data from literature, successfully used for phase diagram calculations of binary Ga-Ge, Ga-Sb and Ge-Sb systems, were used for the prediction of phase equilibria in the ternary Ga-Ge-Sb system. The activities of Ga in the liquid phase were calculated using the Redlich-Kister-Muggianu model and compared with experimental data reported in the literature. The liquidus projection, invariant equilibria and three vertical sections of the Ga-Ge-Sb ternary system were calculated and compared with the experimental results and a good agreement was observed. [ABSTRACT FROM AUTHOR]

The Sm2Ge2O7 and Eu2Ge2O7 germanates have been prepared by solid-state reactions via multistep firing of stoichiometric mixtures of Sm2O3 (Eu2O3) and GeO2 in air at temperatures from 1273 to 1473 K. The molar heat capacity of the samarium and europium germanates has been determined by differential scanning calorimetry in the range 350-1000 K and the Cp(T) data have been used to evaluate their thermodynamic properties. [ABSTRACT FROM AUTHOR]

The Sm2Ge2O7 and Eu2Ge2O7 germanates have been prepared by solid-state reactions via multistep firing of stoichiometric mixtures of Sm2O3 (Eu2O3) and GeO2 in air at temperatures from 1273 to 1473 K. The molar heat capacity of the samarium and europium germanates has been determined by differential scanning calorimetry in the range 350-1000 K and the Cp(T) data have been used to evaluate their thermodynamic properties. [ABSTRACT FROM AUTHOR]

Polycrystalline TbBiGeO and DyBiGeO samples have been prepared by solid-state reactions, by firing stoichiometric mixtures of TbO (DyO), BiO, and GeO in air at 1003, 1073, 1123, 1143, 1173, and 1223 K. The molar heat capacity of the bismuth terbium and bismuth dysprosium germanates has been determined by differential scanning calorimetry. The experimental C ( T) data obtained in the range 350-1000 K have been used to evaluate the thermodynamic functions of the synthesized oxide compounds: enthalpy increment, entropy change, and reduced Gibbs energy. [ABSTRACT FROM AUTHOR]

The heat capacity of monoclinic gadolinium orthotantalate has been determined as a function of temperature by adiabatic and differential scanning calorimetry in the temperature range 8-1323 K. Smoothed heat capacity data have been used to calculate the thermodynamic functions of M-GdTaO with allowance for the contribution of its low-temperature magnetic transformations. [ABSTRACT FROM AUTHOR]

YbSnO and LuSnO have been prepared by solid-state reactions, by firing mixtures of YbO or LuO and SnO at 1473 K, and the molar heat capacity of these compounds (pyrochlore structure) has been determined by differential scanning calorimetry. The C ( T) data have been used to evaluate the thermodynamic properties of the stannates: enthalpy increment, entropy change, and reduced Gibbs energy. [ABSTRACT FROM AUTHOR]