Strontium Metaphosphate, Sr(PO₃)₂

Strontium Metaphosphate, Sr(PO₃)₂, is obtained by dissolving strontium carbonate in excess of phosphoric acid, evaporating, and heating.

Strontium hexa-metaphosphate, Sr₃P₆O₁₈, is formed as a thick white flocculent precipitate by the action of the corresponding sodium salt on excess of strontium nitrate. When dried it forms an amorphous white powder, which is almost insoluble in water and melts to a glass if heated.

The following double phosphates have been described: the orthophosphates, SrKPO₄, SrNaPO₄, and SrNaPO₄.9H₂O; the pyrophosphates, SrK₂P₂O₇ and SrNa₂P₂O₇; and the metaphosphate, NaSr(PO₃)₃.3H₂O. Colani mentions the compounds ThO₂.SrO.P₂O₅ and UO₂.SrO.P₂O₅.