Poly[diaqua­(μ(2)-5-carboxy­pyridine-3-carboxyl­ato-κ(2) N:O (3))hemi(μ(2)-oxalato-κ(4) O (1),O (2):O (1′),O (2′))(μ(4)-pyridine-3,5-dicarboxyl­ato-κ(4) N:O (3):O (3′):O (5))silver(I)terbium(III)]

In the title coordination polymer, [AgTb(C(7)H(3)NO(4))(C(7)H(4)NO(4))(C(2)O(4))(0.5)(H(2)O)(2)](n), the Tb(III) ion is eight-coordinated by three O atoms from three different pydc (H(2)pydc = pyridine-3,5-dicarboxylic acid) ligands, one O atom from one Hpydc ligand, two O atoms from one oxalate ligand and two water mol­ecules in a distorted square-anti­prismatic geometry. The Ag(I) ion is coordinated in an almost linear fashion by two pyridyl N atoms from one pydc and one Hpydc ligand and has weak inter­actions with two carboxyl­ate O atoms. The carboxyl­ate groups of pydc and Hpydc ligands link Tb centers, forming a one-dimensional chain. The oxalate adopts a tetra­dentate bis-chelating coordination mode, connecting the chains into a two-dimensional layer. These layers are further assembled via [Ag(pydc)(Hpydc)] pillars and O—H⋯O and C—H⋯O hydrogen bonds into a three-dimensional coordination framework.