Strontium pyrophosphate has the molecular formula of Sr2P2O7 and the molecular weight of 349.1833 g/mol.
Its CAS number is 765305-66-6. 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:
2SrHPO4 + heat ? Sr2P2O7 +H2O
SrCl2 (aq) +H4P2O7 (aq) ? Sr2P2O7 (solid) + 2HCl (aq)
The solution method produces a hemihydrate,
Sr2P2O7·1/2H2O. This salt decomposes at 575°C to
form β-Sr2P2O7. The transition to the high temperature
form, α-Sr2P2O7 takes place at about 760–780°C.
In the Sr2P2O7 system, the unit-cell parameters of
orthorhombic β-Sr2P2O7 are: a = 8.9839?, b = 13.163 ?,
and c = 5.403 ?. The crystallographic data of Sr2P2O7
are reported to contain two types of sites for Sr2+ ions
in the unit cell.
