Crystal structure of a heterometallic coordination polymer: -poly[[[tetra-aqua-cobalt(II)]-μ-pyridine-2,6-di-carboxyl-ato-calcium(II)-μ-pyridine-2,6-di-carboxyl-ato] dihydrate].

In the crystal of the title polymeric complex, {[CoCa(CHNO)(HO)]·2HO} (), the Co ion is ,,'-chelated by two pyridine-2,6-di-carboxyl-ate anions in a distorted NO octa-hedral geometry, and two carboxyl-ate O atoms of pyridine-2,6-di-carboxyl-ate anions bridge tetra-aqua-calcium(II) units to form polymeric chains propagating along the -axis direction. In the crystal, O-H⋯O and C-H⋯O hydrogen bonds, and offset π-π stacking inter-actions [inter-centroid distances = 3.551 (1) and 3.746 (1) Å] involving inversion-related pyridine rings link the polymeric chains and lattice water mol-ecules to form a supra-molecular three-dimensional framework.