XRD and solid-state NMR study of magnesium oxide-magnesium orthophosphate systems

Abstract Various magnesium oxide–magnesium orthophosphate systems in different Mg/P ratios were synthesized and examined by XRD and 1 H and 31 P MAS NMR. The results thus obtained are compared with those for commercially available pure MgO and Mg 3 (PO 4 ) 2 . The crystallization temperature of magnesium orthophosphate was found to increase with increasing MgO content in the sample. The NMR technique revealed the absence of interactions between the two species. 31 P MAS NMR allowed the amorphous-to-crystalline ratio for magnesium orthophosphate in solids calcined at different temperatures to be determined. Also, 1 H MAS NMR revealed the qualitative nature of hydroxyl sites in the solids.