The preparation methods of magnesium pyrophosphate are as follows: 1. It is prepared by a double decomposition reaction of sodium pyrophosphate solution and magnesium chloride solution. 2. Magnesium ammonium phosphate hexahydrate (NH₄MgPO₄·6H₂O) is heated at above 600℃ for about 2 hours to produce magnesium diphosphate. Magnesium pyrophosphate can also be obtained by mixing an aqueous solution of sodium pyrophosphate with an aqueous solution of magnesium chloride.
Magnesium pyrophosphate is a colorless monoclinic crystal and can be used as a stabilizer in toothpaste and tooth powder.
Magnesium pyrophosphate has the molecular formula
of Mg2P2O7 and the molecular weight of grams per mole.
It may be prepared by the solid-state reaction of the dibasic
orthophosphate, or alternately by the precipitation of a
soluble Mg salt with aqueous pyrophosphoric acid:
2MgHPO4 (or MgNH4PO4) + heat0Mg2P2O7
+H2O (+NH3)
MgCl2 (aq)+H4P2O7 (aq)0Mg2P2O7 (solid)+2HCl (aq)
In the solution method, the result is the hexahydrate,
Mg2P2O7·6H2O. This is a white powder with a CAS
number of 13478-16-5 and a molecular weight of
245.4073 g/mol. Its density is 1.71 g/cm3 and it is relatively
insoluble in water or ethanol but soluble in acids.
colorless; monoclinic [CRC10]
