Poly[di-μ-aqua-di­aqua­bis­(μ₇-oxalato-κ⁹O¹:O¹:O¹,O²:O²:O^2′:O^2′,O^1′:O^1′)calciumdicaesium]

In the title compound, [CaCs₂(C₂O₄)₂(H₂O)₄]_n, the Ca²⁺ 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 CsO₉ polyhedra connected by a face-sharing CaO₆ 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.