Poly[[tetra-aqua-bis-(μ(3)-1H-imidazole-4,5-dicarboxyl-ato)tetra-kis-(μ(2)-1H-imidazole-4,5-dicarboxyl-ato)tricobalt(II)diytterbium(III)] dihydrate].

The asymmetric unit of the title compound, {[Co(3)Yb(2)(C(5)H(2)N(2)O(4))(6)(H(2)O)(4)]·2H(2)O}(n), contains one Yb(III) ion, two Co(II) ions (one situated on an inversion centre), three imidazole-4,5-dicarboxyl-ate ligands, two coordinated water mol-ecules and one uncoordinated water mol-ecule. The Yb(III) ion is seven-coordinated, in a monocapped trigonal prismatic coordination geometry, by six O atoms from three imidazole-4,5-dicarboxyl-ate ligands and one water O atom. Both Co(II) ions are six-coordinated in a slightly distorted octa-hedral geometry. The Co(II) ion that is located on an inversion center is coordinated by two O atoms from two water mol-ecules, as well as two O atoms and two N atoms from two imidazole-4,5-dicarboxyl-ate ligands. The second Co(II) ion is bonded to four O atoms and two N atoms from four imidazole-4,5-dicarboxyl-ate ligands. These metal coordination units are connected by bridging imidazole-4,5-dicarboxyl-ate ligands, generating a three-dimensional network. The crystal structure is further stabilized by N-H⋯O, O-H⋯O and C-H⋯O hydrogen-bonding inter-actions involving the water mol-ecules and the imidazole-4,5-dicarboxyl-ate ligands.