catena-Poly[(μ(2)-3-carb­oxy-5-nitro­benzoato)(μ(3)-5-nitro­benzene-1,3-dicarboxyl­ato)(1,10-phenanthroline)gadolinium(III)]

The crystal structure of the title complex, [Gd(C(8)H(3)NO(6))(C(8)H(4)NO(6))(C(12)H(8)N(2))](n), contains polymeric chains made up of Gd(III) atoms, 1,10-phenanthroline and fully or half-deproton­ated 5-nitro­benzene-1,3-dicarb­oxy­lic acid (H(2) L) ligands. The Gd(III) atom is coordinated in a distorted bicapped trigonal-prismatic fashion by six O atoms from two HL (−) and three L (2−) ligands, and by two N atoms from the 1,10-phenanthroline ligand. The L (2−) ligands bridge the Gd–phenanthroline units, forming chains running parallel to [100]. O—H⋯O hydrogen bonding as well as π–π stacking inter­actions with an inter­planar distance of 3.599 (2) Å assemble neighboring polymeric chains.