Penta-aqua-(5-carb-oxy-pyridine-2-carboxyl-ato-κN,O)(pyridine-2,5-dicarboxyl-ato-κN,O)cerium(III) tetra-hydrate.

In the title compound, [Ce(C(7)H(3)NO(4))(C(7)H(4)NO(4))(H(2)O)(5)]·4H(2)O, the Ce(3+) ion is nine-coordinated by two O atoms and two N atoms from one single and from one double deprotonated pyridine-2,5-dicarboxyl-ate ligand and five water mol-ecules in a distorted monocapped square-anti-prismatic geometry. In the crystal, extensive O-H⋯O hydrogen-bonding inter-actions result in a three-dimensional supra-molecular architecture.