At high pressures, a phase change occurs to a more dense structure with octahedral Fe centres.

In the two polymorphs of the dihydrate, the Fe centre is octahedral with two mutually cis water ligands.

[7] Iron(III) phosphate can be used in steel and metal manufacturing processes.

Its presence is partially responsible for the corrosion resistance of the iron pillar of Delhi.

Iron(III) phosphate is not allowed as food additive in the European Union.