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Abstract  

The thermal behaviour of ammonium oxofluorotitanates (NH4)3TiOF5, (NH4)2TiOF4 and NH4TiOF3 was investigated by thermoanalytical, X-ray and IR spectroscopic methods. The first decomposition stages under quasi-isobaric conditions are characterized by the formation of (NH4)2TiF6 and ammonium oxofluorotitanate with the less content of ammonium and fluorine than in the initial compound. The decomposition process is accompanied by the Ti(IV) reducing due to ammonia evolved. The new ammonium oxofluorotitanate of high volatility was isolated and characterized. Ammonium-containing non-stoichiometric titanium oxyfluorides are the final products of thermal decomposition of ammonium oxofluorotitanates.

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Abstract  

The thermal behaviour of the hexamminechromium hexafluorometallates and [Cr(NH3)6]F3. HF·H2O was investigated by non-reciprocal quasi-isobaric thermal analysis, X-ray diffraction and i.r. spectroscopy. Reduction of chromium(III) was not observed, neither during the decomposition [Cr(NH3)6]F3·HF·H2O nor during the decomposition of any of the title hexamminechromium hexafluorometallates. Obviously this reduction is not promoted by the coordinative Cr−N bonds, neither these in the starting materials nor those in the intermediately formed phases. Under non-reciprocal quasi-isobaric conditions, hexamminechromium hexafluorometallates are ideal precursors for preparing mixed cationic fluorides both in the rhombohedral modification and in the modification of the hexagonal tungsten bronze type structure.

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introduced an approach called Quasi-Isothermal Quasi-Isobaric Thermal Analysis [ 3 , 4 ]. In a later development, Sorensen established the Stepwise Isothermal Analysis method [ 5 ]. SCTA techniques have been based largely on the measurement of

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