Magnesium phosphateMagnesium phosphate is a general term for salts of magnesium and phosphate appearing in several forms and several hydrates: Monomagnesium phosphate: Mg2·nH2O Dimagnesium phosphate: Mg·nH2O Trimagnesium phosphate: Mg32·nH2OAmorphous magnesium phosphate is also claimed.SafetyMagnesium phosphates are listed on the U.S. FDA's Generally recognized as safe list of substances.