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  • Author or Editor: G. Gospodinov x
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Abstract  

The temperature dependence of the molar heat capacities of the tellurites CoTeO3, MnTeO3 and MnTe6O13 are determined. By statistical manipulation of the values obtained, the parameters in the equations for the corresponding compounds showing this dependence are determined using the least-squares method. These equations and the standard molar entropies are used to determine the thermodynamic functions for T'=298.15 K.

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Abstract  

The solubility isotherm of the Sm2O3-SeO2-H2O system was studied at 100°C. The two compounds obtained in the three-component system were identified by the Schreinemakers' method as well as by chemical, thermoanalytical and X-ray diffraction analyses after their isolation in pure state.

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Abstract  

The solubility isotherm of the system Nd2O3-SeO2-H2O at 100C was studied and drawn. All possible selenites of neodymium were obtained and characterized. Thermal decomposition of all phases in the system was studied and its mechanism was described.

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The temperature dependencies of the molar heat capacities of ZnTeO3, Zn2Te3O8, CdTeO3 and CdTe2O5 are determined. The experimental data are statistically processed using the least squares method to determine the parameters in the equations for the corresponding compounds: C p,m=a+b(T/K)-c(T/K)-2. These equations and the standard molar entropies are used to determine ΔT 0 S 0 m, ΔT T H 0 m and (Φ0 mT, 0 H 0 m/T) for T'=298.15 K.

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Abstract  

The solubility of the system Pr2O3-SeO2-H2O at 100°C was studied. The fields of crystallization of Pr2(SeO3)3·H2O, PrH(SeO3)2, Pr(HSeO3)3 were established. The compounds obtained were identified by means of chemical, X-ray and thermal analysis. The thermal decomposition of Pr2(SeO3)3·H2O, PrH(SeO3)2, and Pr(HSeO3)3 was determined.

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Abstract

The temperature dependence of the molar heat capacities of the tellurites PbTeO3, Pb2Te3O8 and Ge(TeO3)2 are determined. By statistical manipulation of the values obtained, the parameters in the equations for the corresponding compounds showing this dependence are determined using the least-squares method. These equations and the standard molar entropies are used to determine the thermodynamic functions Δ0 T S m 0, ΔT T H m 0 and (Φm 00 T H m 0/T) for T′=298.15 K.

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Abstract  

The solubility isotherm of the system La2O3—SeO2—H2O at 100°C was studied. The compounds of the three-component system were identified by the Schreinemakers method as well as by chemical and X-ray phase analyses. Simultaneous TG and DTA analyses of all compounds of the system were made by using a derivatograph. The mechanism of thermal decomposition was described.

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Abstract  

The selenites of scandium are used as new materials in producing instrument and semi-conductor engineering. Like tellurites, they can also be applied as materials for making lasers. The process of producing scandium selenides by the reduction of the corresponding selenites has the advantage of taking place at relatively low temperatures and high rate. In this respect, it is necessary to command methods of obtaining high-purity selenites and to obtain data concerning their thermal stability. A physicochemical study of the system Sc2O3-SeO2-H2O was carried out at 100C in order to find solutions to these problems. The possible compounds in the system at a given temperature were obtained. The compounds were identified by the Schreinemakers' method and also by chemical and X-ray phase analyses. The mechanism of thermal decomposition was determined by means of a derivatograph.

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Abstract  

The temperature dependence of the molar heat capacities of the tellurites Fe2(TeO3)3, Fe2TeO5 and Fe2Te4O11 were determined. By statistical manipulation of the values obtained, the parameters in the equations for the corresponding compounds showing this dependence were determined using the least-squares method. These equations together with the standard molar entropies were used to determine the thermodynamic functions Δ0 T S m 0, ΔT T,H m 0 and (Φm 0 + Δ0 T’ H m 0 / T) for T’=298.15 K.

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