Study of crystallohydrates and anhydrous phases of 12-tungstophosphoric acid by 31P and 1H NMR method

High-water hydrates of 12-tungstophosphoric and 12-molybdophosphoric acids, as well as products of their thermal dehydration and decomposition are investigated by the method of high resolution and 31P, 1H NMR relaxation. Results for molecule mobility and thermal transformations of structure elements and crystallo-hydrates of heteropolyacids (HPA) are given. Oscillating or rotating anion mobility is shown to be possible for high-water HPA. For hexahydrate and the anhydrous phase the character of 31P NMR line is completely determined by phosphorus-proton interaction. The supposition concerning the character of phosphorus distribution in anhydrous and destructed phases of HPA is made