catena-Poly[4,4'-bipyridinium [[tetra-aqua-(pyridine-2,6-dicarboxyl-ato-κO,N,O)cerate(III)]-μ-pyridine-2,6-dicarboxyl-ato-κO:O,N,O-[(pyridine-2,6-dicarboxyl-ato-κO,N,O)cerate(III)]-μ-pyridine-2,6-dicarboxyl-ato-κO,N,O:O] penta-hydrate].

The title compound, {(C(10)H(10)N(2))[Ce(2)(C(7)H(3)NO(4))(4)(H(2)O)(4)]·5H(2)O}(n), is composed of a one-dimensional anionic complex, a doubly protonated 4,4'-bipyridine mol-ecule as a counter-ion and five uncoordinated water mol-ecules. The anion bears two nine-coordinate Ce(III) ions, each with a distorted tricapped trigonal-prismatic geometry. In the crystal, inter-molecular C-H⋯O, N-H⋯O and O-H⋯O hydrogen bonds, as well as π-π inter-actions with centroid-centroid distances of 3.514 (3) Å connect the various components into a supra-molecular structure.