Bis[4-(4-pyridyl)pyridinium] (4-carboxy-pyridine-2,6-dicarboxyl-ato-κO,N,O)(pyridine-2,4,6-tricarboxyl-ato-κO,N,O)ferrate(III) trihydrate.

In the title salt, (C(10)H(9)N(2))(2)[Fe(C(8)H(2)NO(6))(C(8)H(3)NO(6))]·3H(2)O, the Fe(III) atom is O,N,O'-chelated by dianionic and trianionic ligands in a slightly distorted octa-hedral coordination geometry. The cations and ferrate anions are linked into a layered structure; the layers are connected through the uncoordinated water mol-ecules into a hydrogen-bonded three-dimensional supra-molecular structure. One of the uncoordinated water molecules is disordered around an inversion centre and was refined with half-occupancy for each position.