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The dehydration of CoHPO4 · 1.5H2O has been followed by means of thermal analyses at quasi isothermal-isobaric conditions. The intermediates and products prepared in the course of the TA and by calcination of the starting hydrogen phosphate in electric ovens at various temperatures have been analyzed and identified by means of thin-layer chromatography, IR spectroscopy, X-ray diffraction analysis and electron microscopy.

Thermal analyses under quasi-isothermal-isobaric conditions were used to follow the condensation reactions proceeding during the calcination of zinc hydrogenphosphate. Its calcination in an electric oven under isothermal conditions was adopted for preparation of the intermediates and the main product, which were analysed by chromatography, IR spectroscopy, NMR spectroscopy, X-ray analysis and electron microscopy.

The dehydration and condensation reactions taking place during the calcination of Mn1/2Ca1/2(H2PO4)2.2H2O has been followed by means of thermal analyses under quasi-isothermal-isobaric conditions. Isothermal calcination of starting binary dihydrogenphosphate has been also carried out in an electric oven at various temperatures. The reaction products obtained were analyzed by chromatography, IR-spectroscopy, X-ray diffraction analysis, and electron microscopy. The compositions of the calcinates were determined through extraction. The effect of the partial pressure of water vapour has been followed on course, of the condensation reactions and of the formation of the main product: binary cyclotetraphosphate (tetrametaphosphate) MnCaP4O12.

The mechanism of the dehydration and condensation reaction taking place during calcination of Co1/2Ca1/2(H2PO4)2.2H2O has been followed by means of thermal analyses at non-isothermal (dynamic) and at quasi-isothermal-isobaric conditions. Isothermal calcination of starting binary dihydrogenphosphate was carried out in electric oven at various temperatures. The reaction intermediates and products obtained were analyzed by instrumental analytical methods and extraction experiments with solutions of inorganic compounds and with organic reagents. Effect of water vapour pressure has been followed on course, rate and yield of the condensation reactions and of the formation of main considered product-binary cyclo-tetraphosphate (tetrametaphosphate)c-CoCaP4O12.

With the application of thermogravimetry under quasi-isothermal-isobaric conditions, the reaction course of the calcination of Mn(H2PO4 · H2O to give dimanganese cyclotetraphosphate has been studied. Isothermal calcination was also carried out in an electric furnace at various temperatures (200 min). The reaction products were analyzed by chromatography, IR and NMR spectrocopy, and X-ray diffraction analysis. The compositions of the calcinates were determined through extraction with various inorganic and organic solvents.