Poly[[hexa-aqua-(μ(2)-oxalato-κO,O:O,O)bis-(μ(3)-pyridine-2,4-dicarboxyl-ato-κN,O:O:O)dilanthanum(III)] monohydrate].

In the polymeric title compound, {[La(2)(C(7)H(3)NO(4))(2)(C(2)O(4))(H(2)O)(6)]·H(2)O}(n), the La(3+) cation is nine-coordinated in a distorted LaNO(8) tricapped trigonal-prismatic geometry formed by three pyridinedicarboxylate anions, one oxalate anion and three water mol-ecules. The oxalate anion is located on an inversion center. The oxalate and pyridine-dicarboxyl-ate anions bridge the La(3+) cations, forming a two-dimensional polymeric complex parallel to (010). Inter-molecular O-H⋯O hydrogen bonding and weak C-H⋯O hydrogen bonding is present in the crystal structure and π-π stacking [centroid-centroid distance = 3.571 (3) Å] is observed between parallel pyridine rings of adjacent mol-ecules. The uncoordinated water molecule shows an occupancy of 0.5.