Strontium phosphate is the phosphate salt of strontium, with the molecular formula Sr<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>. It is a white solid insoluble in water.
Strontium phosphate is commonly produced by the reaction of soluble strontium compounds, such as strontium nitrate, and a phosphate source, such as phosphoric acid or tripotassium phosphate, in water, resulting in a white precipitate of the tetrahydrate:
Under water, the tetrahydrate slowly hydrolyses to strontium hydroxyapatite (Sr<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub>). The tetrahydrate decomposes to the anhydrous form when heated to 900 ðC.
The anhydrous form can be produced without the presence of water, to avoid hydrolysis, by the heating of ammonium dihydrogen phosphate and strontium carbonate at 1030 ðC and 30 MPa of pressure.