Structure of the calcium pyro­phosphate monohydrate phase (Ca₂P₂O₇·H₂O): towards understanding the dehydration process in calcium pyrophosphate hydrates

The synthesis of single crystals of calcium pyrophosphate monohydrate (CPPM) by diffusion in silica gel at ambient temperature and the structural determination of this phase are reported. Complementarily, data from synchrotron X-ray diffraction on a CPPM powder sample have been fitted to the crystal parameters. Finally, the relationship between the resolved structure for the CPPM phase and the structure of the tetra­hydrated calcium pyrophosphate β phase (CPPT-β) is discussed.