Crystal structure of a heterometallic coordination polymer: poly[di-aqua-bis-(μ-benzene-1,3,5-tri-carboxyl-ato)dicalcium(II)copper(II)].

In the title complex, [CaCu(CHO)(HO)] , the Ca and Cu cations are bridged by the benzene-1,3,5-tri-carboxyl-ate anions (BTC) to form the coordination polymer, in which each BTC anion bridges two Cu and five Ca cations with a μ coordination mode. The Cu cation, located at an inversion centre, is in a nearly square-planar geometry defined by four O atoms from four bridging BTC anions, while the Ca cation is in a distorted octa-hedral geometry defined by five O atoms from bridging BTC anions and one water mol-ecule. O-H⋯O hydrogen bonds between coordinating water mol-ecules and carboxyl groups further stabilize the structure; π-π stacking is also observed between parallel benzene rings, the centroid-to-centroid distance being 3.357 (2) Å.