A MAGIC-ANGLE SPINNING ³¹P NMR INVESTIGATION OF CRYSTALLINE AND GLASSY INORGANIC PHOSPHATES

³¹PNMR spectra of several inorganic phosphates have been examined both in the crystalline and the glassy states. The parameter (Z_eff/r)q clearly demarcates ortho-, pyro- and meta-phosphates in terms of the ³¹P chemical shifts . Based on such a diagram, inorganic phosphate glasses are found to consist essentially of metaphosphate units. NMR resonance of the glasses are generally much broader than those of crystalline phosphates.