Calcium peroxyphosphate has the formula of
CaHPO5 as the monooxyphosphate or Ca2P2O8 as the
dioxyphosphate. For preparation of the monooxyphosphate,
the acid is first prepared by adding P2O5 to 30% hydrogen peroxide and then adding the hydroxide or carbonate to the acid:
P2O5 + 2H2O2 +H2O ? 2H3PO5
Ca(OH)2 +H3PO5 ? CaHPO5 +H2O
The phosphorus pentoxide powder was suspended in
carbon tetrachloride under stirring while cooled in an ice
bath. Aqueous hydrogen peroxide was added drop wise
to this suspension to form H3PO5. Calcium carbonate or
calcium hydroxide slurry was added slowly to the
formed inorganic concentrated peroxymonophosphoric
acid layer in an ice bath. The precipitate was then filtered.
The result is a dihydrate, CaHPO5·2H2O.
