Crystal structure of a polymeric calcium levulinate dihydrate: catena-poly[[di­aqua­calcium]-bis­(μ(2)-4-oxo­butano­ato)]

In the title calcium levulinate complex, [Ca(C(5)H(7)O(3))(2)(H(2)O)(2)](n), the Ca(2+) ion lies on a twofold rotation axis and is octa­coordinated by two aqua ligands and six O atoms from four symmetry-related carboxyl­ate ligands, giving a distorted square-anti­prismatic coordination stereochemistry [Ca—O bond-length range = 2.355 (1)–2.599 (1) Å]. The levulinate ligands act both in a bidentate carboxyl O,O′-chelate mode and in a bridging mode through one carboxyl O atom with an inversion-related Ca(2+) atom, giving a Ca⋯Ca separation of 4.0326 (7) Å. A coordination polymeric chain structure is generated, extending along the c-axial direction. The coordinating water mol­ecules act as double donors and participate in intra-chain O—H⋯O hydrogen bonds with carboxyl O atoms, and in inter-chain O—H⋯O hydrogen bonds with carbonyl O atoms, thus forming an overall three-dimensional structure.