Magnesium Phosphate - Mg<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>

What is Magnesium Phosphate?

Magnesium Phosphate, Mg3(PO4)2 is an important mineral found in bones, in the seeds of many plants, and in a number of minerals. It is taken as a source of supplemental dietary magnesium. Tribasic magnesium phosphate may be prepared by the interaction of magnesium chloride, or sulfate with the phosphate salt. The solution is easily prepared by agitating some of the salt with carbon dioxide free water for several hours.

Other name – Trimagnesium diphosphate, Phosphoric acid magnesium salt


Magnesium Phosphate


2.195 g/mL at 25 °C(lit)

Molecular Weight/ Molar Mass

262.855 g/mol

Hydrogen Bond Acceptor


Melting Point

1,184 °C

Chemical Formula


Magnesium Phosphate Structure – Mg3(PO4)2

Magnesium Phosphate

Physical Properties of Magnesium Phosphate – Mg3(PO4)2


No odour


White crystalline powder

Covalently-Bonded Unit







Soluble in salt solution

Chemical Properties of Magnesium Phosphate – Mg3(PO4)2

  • Magnesium Phosphate is a salt when treated with water forms phosphoric acid and magnesium hydroxide. The chemical equation is given below.
  • Mg3(PO4)2 + H2O → H3PO4 + Mg(OH)2

  • Magnesium Phosphate reacts with hydrochloric acid forms phosphoric acid and magnesium chloride.
  • Mg3(PO4)2 + HCl → MgCl2 + H3PO4

Uses of Magnesium Phosphate – Mg3(PO4)2

  • Used as a source for both magnesium and phosphorus. It is used in minimal supplement.
  • Used in the prevention of vitamin E deficiency.
  • Used in foods at levels not to exceed current good manufacturing practice. The ingredient also may be used in infant formula.
  • Used as a nutrient, pH control agent and stabilizer.

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