Solvent water tapes in two hydrates of μ‐oxo‐bis­[bis­(2,2′‐bipyridine‐κ2N,N′)(sulfato‐κO)iron(III)]

The title compound, [Fe₂O(SO₄)₂(C₁₀H₈N₂)₄], crystallizes as two different hydrates, viz. 11H₂O, (I), and 15H₂O, (II). The complex is binuclear, in which the two Fe^III atoms are coordinated in an octa­hedral geometry to four N atoms from the two bipyridine ligands, to one O atom from the sulfate ion and to an oxide ion on a twofold axis, which acts as a bridge between the symmetry‐related units. The Fe⋯Fe separation is 3.556 (4) Å and the Fe—O—Fe angle is 161.6 (2)° in (I); the corresponding values are 3.544 (1) Å and 165.8 (2)° in (II). In (II), one of the O atoms of the sulfate ion is disordered over two positions. In both compounds, the solvent water mol­ecules form slightly different one‐dimensional hydrogen‐bonded networks which pass along the c axis of the unit cell. In (I), three solvent water mol­ecules and, in (II), one solvent water mol­ecule, are situated on the twofold axis. In both (I) and (II), the central O atom of the metal complex lies on a twofold axis.