Preparation
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.
Description
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/cm
3 and it is relatively
insoluble in water or ethanol but soluble in acids.
