A novel one-dimensional Co^II coordination polymer: catena-poly[[hexa­aqua­cobalt(II)] [[diaqua­bis­(sulfato-[kappa]O)cobalt(II)]-[mu]-4,4'-bipyridine-[kappa]²N:N'] [[triaqua­(sulfato-[kappa]O)cobalt(II)]-[mu]-4,4'-bipyridine-[kappa]²N:N']]

The title compound, {[Co(H₂O)₆][Co(SO₄)(C₁₀H₈N₂)(H₂O)₃][Co(SO₄)₂(C₁₀H₈N₂)(H₂O)₂]}_n, contains three crystallographically unique Co^II centres, all of which are in six-coordinated environments. One Co^II centre is coordinated by two bridging 4,4'-bipyridine (4,4'-bipy) ligands, one sulfate ion and three aqua ligands. The second Co^II centre is surrounded by two N atoms of two 4,4'-bipy ligands and four O atoms, i.e. two O atoms from two monodentate sulfate ions and two from water mol­ecules. The third Co^II centre forms part of a hexaaquacobalt(II) ion. In the crystal structure, there are two different one-dimensional chains, one being anionic and the other neutral, and adjacent chains are arranged in a cross-like fashion around the mid-point of the 4,4'-bipy ligands. The structure features O-H...O hydrogen-bonding inter­actions between sulfate anions and water mol­ecules, resulting in a three-dimensional supra­molecular network.