catena-Poly[[diaqua-calcium(II)]-bis-(μ-quinoline-3-carboxyl-ato)].

In the title complex, [Ca(C(10)H(6)NO(2))(2)(H(2)O)(2)](n), the Ca(II) ion is eight-coordinated by six carboxyl-ate O atoms from four separate quinoline-3-carboxyl-ate ligands, two of which are bidentate chelate and two bridging, and two water mol-ecules in a distorted square-anti-prismatic geometry. The bridging groups form a polymeric chain substructure extending along the c axis, the chains being connected by coordinated-water O-H⋯N and O-H⋯O(carboxyl-ate) hydrogen bonds into a three-dimensional framework structure.