Trimagnesium phosphate describes
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
s with formula Mg
3(PO
4)
2.xH
2O. They are
magnesium acid salts of
phosphoric acid, with varying amounts of
water of crystallization: x = 0, 5, 8, 22.
The octahydrate forms upon reaction of stoichiometric quantities of
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 ...
(tetrahydrate) with
magnesium hydroxide.
:Mg(H
2PO
4)
2•4H
2O + 2 Mg(OH)
2 → Mg
3(PO
4)
2•8H
2O
The octahydrate is found in nature as the mineral
bobierrite.
The anhydrous compound is obtained by heating the hydrates to 400 °C. It is isostructural with cobalt(II) phosphate. The metal ions occupy both
octahedral (six-coordinate) and pentacoordinate sites in a 1:2 ratio.
Safety
Magnesium phosphate tribasic is listed on the FDA's
generally recognized as safe, or GRAS, list of substances.
See also
*
Magnesium phosphate
Magnesium phosphate is a general term for salts of magnesium and phosphate appearing in several forms and several hydrates:
* Monomagnesium phosphate (Mg(H2PO4)2).xH2O
* Dimagnesium phosphate (MgHPO4).xH2O
* Trimagnesium phosphate (Mg3(PO4)2 ...
References
{{Phosphates
Acid salts
Phosphates
Magnesium compounds
E-number additives