Poly[bis(μ2-pyrimidine-2-carboxylato-κ4O,N:O′,N′)calcium]

In the crystal structure of the title polymeric complex, [Ca(C5H3N2O2)2]n, the CaII cation has site symmetry overline{4}m2 and is N,O-chelated by four pyrimidine-2-carboxylate anions in a square-antiprismatic geometry. The planar pyrimidine-2-carboxylate anion is located on a crystallographic special position, three C atoms have site symmetry 2mm, while the carboxyl O atom, the pyrimidine N atom and the other C atom have site symmetry m. Each pyrimidine-2-carboxylate anion bridges two CaII cations, forming polymeric sheets extending parallel to (001). π–π stacking exists between parallel pyrimidine rings [centroid–centroid distance = 3.6436 (6) Å] of adjacent polymeric sheets. Weak C—H...O hydrogen bonding is also observed between these sheets.