iron(iii) pyrophosphate iron(iii) pyrophosphate iron(iii) pyrophosphate is an inorganic chemical compound with the formula fe4(p2o7)3. iron(iii) pyrophosphate names other names ferric pyrophosphate identifiers cas number 10058-44-3 (anhydrous)10049-18-0 (nonahydrate)1802359-96-1 3d model (jsmol) interactive image chebi chebi:132767 chemspider 2325834994433 drugbank db09147db13995 echa infocard 100.030.160 ec number 233-190-0 pubchem cid 24877 unii qk8899250f1zjr117wbq (nonahydrate)uby79oco9g comptox dashboard (epa) dtxsid6047600 inchi key: cadnyozxmikypr-uhfffaoysa-binchi=1s/4fe.3h4o7p2/c;;;;3*1-8(2,3)7-9(4,5)6/h;;;;3*(h2,1,2,3)(h2,4,5,6)/q4*+3;;;/p-12 smiles .o=p()()op(=o)()..o=p()()op(=o)()..o=p()()op(=o)(). properties chemical formula fe4(p2o7)3 molar mass 745.224 (anhydrate)907.348 (nonahydrate) appearance yellow solid (nonahydrate) solubility in water insoluble pharmacology legal status ca: ℞-only us: ℞-only except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references synthesis 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: 3 na4p2o7(aq) + 4 fecl3(aq) → fe4(p2o7)3(s) + 12 nacl(aq)