Iron(III) pyrophosphate is an inorganic chemical compound with the formula Fe<sub>4</sub>(P<sub>2</sub>O<sub>7</sub>)<sub>3</sub>.
Anhydrous iron(III) pyrophosphate can be prepared by heating the mixture of iron(III) metaphosphate and iron(III) phosphate under oxygen with the stoichiometric ratio 1:3. The reactants can be prepared by reacting iron(III) nitrate nonahydrate with phosphoric acid.
It can be also prepared via the following reaction: