CALCIUM-PHOSPHATE CRYSTALLIZATION WITH MA GNESIUM

Formation and evolution of calcium phosphates are investigated, at 37- degrees-C, in urine and aqueous solutions whose concentrations in calc ium and magnesium are close to those of urine. Although the solutions are supersaturated with respect to all calcium phosphates, only an amo rphous phase (ACP) and brushite (B) precipitate at time zero. Later on , ACP transforms either into whitlockite (W) or into apatite (HAP) dep ending on the solution composition. Phase transformations are discusse d in terms of supersaturation, parameter which includes concentrations and pH. It is also shown that magnesium is a powerful inhibitor of th e evolution towards HAP.