Poly[di-μ-aqua-di­aqua­bis­(μ(7)-oxalato-κ(9) O (1):O (1):O (1),O (2):O (2):O (2′):O (2′),O (1′):O (1′))calciumdicaesium]

In the title compound, [CaCs(2)(C(2)O(4))(2)(H(2)O)(4)](n), the Ca(2+) ion, lying on a twofold rotation axis, is coordinated by four O atoms from two oxalate ligands and two bridging water mol­ecules in an octa­hedral geometry. The Cs(+) ion is coordinated by seven O atoms from six oxalate ligands, one bridging water and one terminal water mol­ecule. The oxalate ligand displays a scarce high denticity. The structure contains parallel chain units runnig along [10-1], formed by two edge-sharing Cs polyhedra connected by CsO(9) polyhedra connected by a face-sharing CaO(6) octahedron. These chains are further linked by the oxalate ligands to build up a three-dimensional framework. O—H⋯O hydrogen bonds involving the water mol­ecules and the carboxyl­ate O atoms enhance the extended structure.