Thermodynamic analysis of formation reactions of condensed lithium-, rubidium- and cesium phosphates

Thermodynamic analysis has been conducted and the mechanism of the formation of condensed cesium phosphates has been elucidated. The study has been performed with the help of differential thermal and X-ray phase analyses. Temperature dependence of isobaric-isothermal potential has been found for each reaction. Dehydration of cesium dihydroorthophosphate proceeds in two stages. At 156 deg dihydropyrophosphate is formed and at 320 deg - cesium metaphosphate. Enthalpy and entropy of cesium metaphosphate formation from Cs2H2P2O7 is 22600 cal/mol and 38.14 cal/mol at 25 deg. Condensation of disubstituted cesium orthophosphate with the formation of normal pyrophosphate begins from 530 deg