The thermal excitation of artificial brushite in dried air and normal atmosphere generates the following reactions: We could not register the monotropic γ→β and β→χ transformations by DTA. At low pH2O values unstable inordinate intermediates are formed until the exothermic transformation, at high pH2O value and in water a stable, secondary hydrogen phosphate of ordinate crystal lattice and γ-pyrophosphate originate. The amorphous intermediate compounds are pseudomorphous with the initial brushite. The lack of H2O hinders, whereas the excess of H2O promotes the formation of nuclei and crystallization of monetite and as a result of this its thermal existence region is expanded. Accordingly, during the dehydratation process in dry air the decrease of the
