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.

catena-Poly[1,4-dihy­droxy-1,4-di­azoniabicyclo­[2.2.2]octane [aqua­tri-[mu]-chlorido-trichloridodicuprate(II)]]

The title compound, {(C₆H₁₄N₂O₂)[Cu₂Cl₆(H₂O)]}_n, consists of 1,4-dihy­droxy-1,4-diazo­niabicyclo­[2.2.2]octane dications and one-dimensional inorganic anionic {[Cu₂Cl₆(H₂O)]^2-}_n chains in which both five-coordinate [CuCl₃(H₂O)]^- and five-coordinate [CuCl₃]^- units exist. These two distinct type of unit are linked together by one chloride ion and are bridged across centres of inversion to further units of their own type through two chloride ions, giving rise to novel polymeric zigzag chains parallel to the c axis. The chains are connected by O-H...Cl hydrogen bonds to produce R₂⁴(16) ring motifs, resulting in two-dimensional layers parallel to the ac plane. These layers are linked into a three-dimensional framework with the organic cations via O-H...Cl hydrogen bonds. Hydrogen bonding between the chains, and between the chains and the organic cations, provides stability to the crystal structure.