Poly[triaqua-tris-(μ(4)-pyridine-3,5-dicarboxyl-ato)dicerium(III)].

The asymmetric unit of the title compound, [Ce(2)(C(7)H(3)NO(4))(3)(H(2)O)(3)](n), contains two Ce(III) cations, three pyridine-3,5-dicarboxyl-ate (pyd) anions and three coordinated water mol-ecules. One Ce(III) cation is coordinated by seven carboxyl-ate O atoms from six pyd anions and two water mol-ecules in a square-face-capped square-anti-prismatic geometry. Another Ce(III) cation is coordinated by seven O atoms from six pdy anions and one water mol-ecule in a bicapped trigonal-prismatic geometry. The pdy anions bridge the Ce(III) cations, forming the three-dimensional polymeric structure. The crystal structure contains extensive O-H⋯O, O-H⋯N and weak C-H⋯O hydrogen bonds. π-π stacking is present in the crystal structure, the shortest centroid-centroid distance between parallel pyridine rings being 3.509†(4)†à .