Poly[μ-aqua-diaqua(μ(3)-1H-benzimid-azole-5-carboxylato-κN:O,O')(μ(2)-1H-benzimidazole-5-carboxylato-κN:O:O')-μ(5)-sulfato-μ(4)-sulfato-tri-cadmium].

The asymmetric unit of the title compound, [Cd(3)(C(8)H(5)N(2)O(2))(2)(SO(4))(2)(H(2)O)(3)](n), contains three Cd(II) ions, two sulfate anions, two 1H-benzimidazole-5-carboxyl-ate (H(2)bic) ligands and three coordinated water mol-ecules. One Cd(II) ion is six-coordinated and exhibits a distorted octa-hedral geometry, while the other two Cd(II) ions are seven-coordinated, displaying a distorted penta-gonal-bipyramidal geometry. The Cd(II) ions are bridged by two types of sulfate anions, producing inorganic chains along [100]. These chains are further connected by the H(2)bic ligands, leading to a three-dimensional framework. N-H⋯O and O-H⋯O hydrogen bonds and π-π inter-actions between the imidazole and benzene rings [centroid-centroid distances = 3.953 (2), 3.507 (2), 3.407 (2) and 3.561 (2) Å] further stabilize the crystal structure.