Dimagnesium phosphate
# Dimagnesium phosphate

Dimagnesium phosphate is a compound with formula $MgHPO_4.$ It is a $Mg^{2+}$ salt of monohydrogen phosphate. The trihydrate is well known, occurring as a mineral.

It can be formed by reaction of stoichiometric quantities of magnesium oxide with phosphoric acid.

    MgO + $H_3PO_4$ → $MgHPO_4$ + $H_2O$

Dissolving monomagnesium phosphate in water, forms phosphoric acid and depositing a solid precipitate of dimagnesium phosphate trihydrate:

    $Mg(H_2PO_4)_2$ + 3 $H_2O$ → $Mg(HPO_4)^.3H_2O$ + $H_3PO_4$

The compound is used as a nutritional supplement, especially for infants and athletes. Its E number is E343.

