Crystal structure of a heterometallic coordination polymer: poly[di­aqua­bis­(μ(7)-benzene-1,3,5-tri­carboxyl­ato)dicalcium(II)copper(II)]

In the title complex, [Ca(2)Cu(C(9)H(3)O(6))(2)(H(2)O)(2)](n), the Ca(II) and Cu(II) cations are bridged by the benzene-1,3,5-tri­carboxyl­ate anions (BTC(3−)) to form the coordination polymer, in which each BTC(3−) anion bridges two Cu(II) and five Ca(II) cations with a μ(7) coordination mode. The Cu(II) cation, located at an inversion centre, is in a nearly square-planar geometry defined by four O atoms from four bridging BTC(3−) anions, while the Ca(II) cation is in a distorted octa­hedral geometry defined by five O atoms from bridging BTC(3−) anions and one water mol­ecule. O—H⋯O hydrogen bonds between coordinating water mol­ecules 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.