catena-Poly[4,4′-bipyridinium [[tetra­aqua­(pyridine-2,6-dicarboxyl­ato-κ(3) O (2),N,O (6))cerate(III)]-μ-pyridine-2,6-dicarboxyl­ato-κ(4) O (2):O (2′),N,O (6)-[(pyridine-2,6-dicarboxyl­ato-κ(3) O (2),N,O (6))cerate(III)]-μ-pyridine-2,6-dicarboxyl­ato-κ(4) O (2),N,O (6):O (6′)] penta­hydrate]

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 mol­ecule as a counter-ion and five uncoordinated water mol­ecules. The anion bears two nine-coordinate Ce(III) ions, each with a distorted tricapped trigonal–prismatic geometry. In the crystal, inter­molecular C—H⋯O, N—H⋯O and O—H⋯O hydrogen bonds, as well as π–π inter­actions with centroid–centroid distances of 3.514 (3) Å connect the various components into a supra­molecular structure.