catena-Poly[iron(II)-bis-{μ-5-carb-oxy-2-[(1H-1,2,4-triazol-1-yl)meth-yl]-1H-imidazole-4-carboxyl-ato}].

In the title coordination polymer, Fe(C(8)H(6)N(5)O(4))(2) {or FeL(2),where HL = 2-[(1H-1,2,4-triazol-1-yl) meth-yl]-1H-imidazole-4,5-dicarb-oxy-lic acid)}, the Fe(II) ion, located on an inversion centre, is six-coordinated by two O atoms and four N atoms from two L(-) ligands in a distorted octa-hedral geometry [Fe-O = 2.1452 (13), Fe-N = 2.1316 (14) and 2.2484 (15) Å]. There is an intra-molecular O-H⋯O hydrogen bond in each L(-) ligand. Being an effective tridentate bridging ligand, the deprotonated L(-) anions link two Fe(II) atoms, yielding a chain-like polymer propagating along [100]. In the crystal, these polymer chains are linked via N-H⋯N hydrogen bonds, forming a two-dimensional network.