trans-Tetra-aqua-bis-[1,3-bis-(4-pyrid-yl)propane-κN]cobalt(II) biphenyl-4,4'-disulfonate monohydrate.

In the title compound, [Co(C(13)H(14)N(2))(2)(H(2)O)(4)](C(12)H(8)O(6)S(2))·H(2)O, the cation, anion and uncoordinated water mol-ecule have crystallographically imposed twofold symmetry. The cobalt(II) atom exhibits a slightly distorted octa-hedral coordination geometry provided by two N atoms from two 1,3-bis-(4-pyrid-yl)propane ligands and the O atoms from four water mol-ecules. The dihedral angle between the pyridine rings in the ligand is 86.14†(11)°, whereas the dihedral angle formed by the symmetry-related benzene rings in the anion is 35.81†(12)°. In the crystal, cations, anions and water mol-ecules are linked into layers parallel to the ac plane by O-H⋯O and O-H⋯N hydrogen-bond inter-actions. The layers are further connected into a three-dimensional network by C-H⋯O hydrogen bonds.