Trimagnesium phosphate
Chemical compound / From Wikipedia, the free encyclopedia
This article is about Magnesium phosphate tribasic. For other uses, see magnesium phosphate.
Trimagnesium phosphate describes inorganic compounds with formula Mg3(PO4)2.xH2O. They are magnesium acid salts of phosphoric acid, with varying amounts of water of crystallization: x = 0, 5, 8, 22.[2]
Quick Facts Names, Identifiers ...
Names | |
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IUPAC name
Trimagnesium diphosphate | |
Other names
magnesium phosphate, phosphoric acid, magnesium salt (2:3), tertiary magnesium phosphate, trimagnesium phosphate | |
Identifiers | |
3D model (JSmol) |
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ChemSpider | |
ECHA InfoCard | 100.028.931 |
EC Number |
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E number | E343 (antioxidants, ...) |
15662 | |
PubChem CID |
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UNII | |
CompTox Dashboard (EPA) |
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Properties | |
Mg3O8P2 | |
Molar mass | 262.855 g·mol−1 |
Appearance | White crystalline powder |
Melting point | 1,184 °C (2,163 °F; 1,457 K) |
Insoluble | |
Solubility product (Ksp) |
1.04×10−24[1] |
Solubility | Soluble in salt solution |
−167·10−6 cm3/mol (+4 H2O) | |
Hazards | |
NFPA 704 (fire diamond) | |
Flash point | N/A |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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The octahydrate forms upon reaction of stoichiometric quantities of monomagnesium phosphate (tetrahydrate) with magnesium hydroxide.
- Mg(H2PO4)2•4H2O + 2 Mg(OH)2 → Mg3(PO4)2•8H2O
The octahydrate is found in nature as the mineral bobierrite.[3]
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.[4]