13466-21-2

White powder. Soluble in acids and ammonium salts; very slightly soluble in water.

Barium pyrophosphate has the molecular formula of Ba2P2O7 and the molecular weight of 448.5973 g/mol. It has the CAS number of 13466-21-2 and may be prepared by the solid-state reaction of the dibasic orthophosphate, or alternately by the precipitation of a soluble Ba salt with aqueous pyrophosphoric acid:
2Ba HPO4 + heat ? Ba2P2O7 +H2O
BaCl2 (aq) +H4P2O7 (aq) ? Ba2P2O7 (s) + 2HCl (aq)
The solution method produces a dihydrate, Ba2P2O7·2H2O.

Ba₂P₂O₇ is a promising phosphor host material, showing different emission properties upon doping with rare earth and other elements. Bi doped Ba₂P₂O₇ crystals exhibit broadband NIR photoluminescence.