Trimagnesium 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]

Trimagnesium phosphate
Names
IUPAC name
Trimagnesium diphosphate
Other names
magnesium phosphate, phosphoric acid, magnesium salt (2:3), tertiary magnesium phosphate, trimagnesium phosphate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.028.931 Edit this at Wikidata
EC Number
  • 231-824-0
E number E343 (antioxidants, ...)
15662
UNII
  • Key: GVALZJMUIHGIMD-UHFFFAOYSA-H
  • InChI=1S/3Mg.2H3O4P/c;;;2*1-5(2,3)4/h;;;2*(H3,1,2,3,4)/q3*+2;;/p-6
  • [O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[Mg+2].[Mg+2].[Mg+2]
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
1.04×10−24[1]
Solubility Soluble in salt solution
−167·10−6 cm3/mol (+4 H2O)
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Flash point N/A
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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]

Safety

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Magnesium phosphate tribasic is listed on the FDA's generally recognized as safe, or GRAS, list of substances.[5]

See also

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References

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  1. ^ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–188. ISBN 978-1138561632.
  2. ^ Klaus Schrödter; Gerhard Bettermann; Thomas Staffel; Friedrich Wahl; Thomas Klein; Thomas Hofmann (2008). "Phosphoric Acid and Phosphates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_465.pub3. ISBN 978-3527306732. S2CID 94458523.
  3. ^ "magnesium phosphate - Compound Summary". Retrieved 29 May 2012.
  4. ^ Nord, A. G.; Stefanidis, T. (1983). "Structure of cobalt(II) phosphate Structure Refinements of Co3(PO4)2. A Note on the Reliability of Powder Diffraction Studies". Acta Chemica Scandinavica A. 37: 715–p721. doi:10.3891/acta.chem.scand.37a-0715.
  5. ^ "TRIMAGNESIUM PHOSPHATE". Retrieved 29 May 2012.