Monomagnesium phosphate

Monomagnesium phosphate is one of the forms of magnesium phosphate. It is a magnesium acid salt of phosphoric acid with the chemical formula Mg(H₂PO₄)₂.
Di- and tetrahydrates are known also. It dissolves in water, forming phosphoric acid and depositing a solid precipitate of Mg(HPO₄)·3H₂O, dimagnesium phosphate.^[2]

Monomagnesium phosphate^[1]

Names
Other names Monomagnesium orthophosphate; Magnesium dihydrogen phosphate; Magnesium phosphate monobasic; Magnesium biphosphate; Acid magnesium phosphate
Identifiers
CAS Number	13092-66-5 (Anhydrous) Y 15609-80-0 (Dihydrate) Y 15609-87-7 (Tetrahydrate) Y
3D model (JSmol)	Interactive image
ChemSpider	451008 N
ECHA InfoCard	100.032.716
E number	E343(i) (antioxidants, ...)
PubChem CID	516950
UNII	AA2L7VX59K (Anhydrous) Y H3992158BT (Dihydrate) Y XG6J0SHI70 (Tetrahydrate) Y
CompTox Dashboard (EPA)	DTXSID00872542
InChI InChI=1S/Mg.2H3O4P/c;2*1-5(2,3)4/h;2*(H3,1,2,3,4)/q+2;;/p-2 N Key: QQFLQYOOQVLGTQ-UHFFFAOYSA-L N InChI=1/Mg.2H3O4P/c;2*1-5(2,3)4/h;2*(H3,1,2,3,4)/q+2;;/p-2 Key: QQFLQYOOQVLGTQ-NUQVWONBAA
SMILES OP(=O)(O)[O-].OP(=O)(O)[O-].[Mg+2]
Properties
Chemical formula	H4MgO8P2
Molar mass	218.277 g·mol−1
Appearance	White, odorless, crystalline powder
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

As a food additive, it is used as an acidity regulator and has the E number E343.