A potential molecular ferroelectric material: poly[[bis­(1-aza-4-azonia­bicyclo[2.2.2]octane)di-μ₃-chlorido-tetra-μ₂-chlorido-dichlorido­tri­cadmium(II)] dihydrate]

The title compound, {[Cd₃(C₆H₁₃N₂)₂Cl₈]·2H₂O}_n, consists of pendant proton­ated cationic diamine ligands bonded to an anionic one-dimensional coordination polymer chlorido­cadmate scaffold. Each coordination chain features two kinds of Cd^II centre, each with distorted octa­hedral coordination geometry. One Cd^II cation lies on a centre of inversion and is coordinated by six bridging chloride ligands, while the other is coordinated by four bridging chloride ligands, one terminal chloride ligand and a 1-aza-4-azonia­bicyclo­[2.2.2]octane aza N atom. This gives a reversible corner-sharing half-cubic linear polymer that lies along the crystallographic a direction. The chains inter­act through hydrogen bonding with solvent water, with each water mol­ecule accepting one N—H...O inter­action from a cation and donating to two O—H...Cl inter­actions with anionic chains, thus linking three separate chains and completing the packing structure.