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Abstract  

Differential thermal analysis (DTA) and X-ray powder diffraction (XRD) were used to study phase equilibria, established in air in the V2O5-Sb2O4 system up to 1000C. It has been found that there is a new phase =SbVO5. The =SbVO5 has been prepared by two methods: by heating equimolar mixtures of V2O5 and α-Sb2O4 in air and by oxidation of the known phase of rutile type obtained in pure argon at temperatures between 550 and 650C. Thermal decomposition of =SbVO5 in the solid state starts at 710C giving off oxygen. The results provide a basis for constructing only a part of the phase diagram of the investigated system (up to 50.00 mol% Sb2O4).

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Abstract  

The use of XRD and DTA methods has allowed studies on the interaction of the SbVO5 and MoO3, taking place in the solid state and in the medium of ambient air. The experimental results of XRD and DTA for all the samples showed the presence of a novel phase, i.e. Sb3V2Mo3O21 apart from various amounts of MoO3 and V9Mo6O40 or SbVO5 and V2O5(s.s.). The SbVO5–MoO3 system is not a real two-component system over the entire range of component concentrations up to the solidus line.

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The phase equilibria in the total range of component concentrations in the V2O5-Cr2O3 system up to 1000 °C were studied by means of phase powder diffraction and DTA. Two compounds exist in the system: CrVO4, melting incongruently at 860±5 °C, and Cr2V4O13, which decomposes in the solid state at 640±5 °C to CrVO4(s) and V2O5(s). At 645±5 °C, CrVO4 and V2O5 form a eutectic mixture with the CrVO4 content not exceeding 2% mol.

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]. According to [ 1 , 8 ] this compound crystallizes in the orthorhombic system with Pnma space group ( a = 7.812(2), b = 5.740(1), c = 10.056(2) Å). We found no reported data on its melting point, too. Studies of phase equilibria which occur in

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Introduction The experimental investigation of the Dy–Al–Si system is part of an ongoing research project carried out by our group with the aim to clarify the phase equilibria of ternary systems of aluminium and silicon with

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Abstract  

The vaporization of samples of different chemical and phase compositions in the systems CsCl-LnCl3 (Ln=Ce, Nd) was investigated in the temperature range between 850 and 1050 K by the use of Knudsen effusion mass spectrometry. The gaseous species CsCl, Cs2Cl2, LnCl3, Ln2Cl6 and CsLnCl4 were identified in the vapour and their partial pressures were determined. The thermodynamic activities of CsCl, and LnCl3 and the free enthalpies of formation for the phases Cs3LnCl6(s) were determined at 950 K in the two phase fields {liquid+Cs3LnCl6(s)}. The correlations between the condensed phase equilibria and the partial pressures of the vapour components at the phase boundaries are discussed and illustrated with the present experimental data.

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Abstract  

A phase diagram of the V2O5–Fe8V10W16O85 system were carried out using XRD and DTA methods. In addition, an indexing of Fe8V10W16O85 powder diffraction pattern was made and its basic crystallographic parameters were determined. Finally, the phase was studied using IR spectroscopy.

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Abstract  

The phase diagram for the CuBr−TlBr system was investigated using the differential thermal analysis completed by the X-ray powder diffraction data. Three intermediate phases were found: Tl2CuBr3 (stable from room temperature up to 234°C where decomposes in the solid state), Tl3Cu2Br5 (stable between 168°C and its incongruent melting point 262°C) and a nonstochiometric δ phase (centered about 75 mol% CuBr and stable above about 240°C).

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Abstract  

Phase equilibria in the partial system Mg2P2O7−Na8Mg6(P2O7)5−NaPO3−Mg(PO3)2 were examined by differential thermal analysis and powder X-ray diffraction. It was found that there are six sections in the composition range under investigation.

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