[Cu(2)(HF(2))(H(2)O)(8)][AlF(6)]·2H(2)O

The title compound, octaaqua­(hydrogendifluorido)­di­cop­per(II) hexa­fluoridoaluminate dihydrate, was obtained under hydro­thermal conditions. The structure is isotypic with that of the analogous Fe(III) compound, [Cu(2)(HF(2))(H(2)O)(8)][FeF(6)]·2H(2)O. The coordination sphere of the Cu(II) atom is formed by one F and three water O atoms at short distances < 2 Å and is augmented by two additional water O atoms at significantly longer distances, leading to a considerably distorted octa­hedral environment. By edge-sharing, these octa­hedra form dimeric [Cu(2)(HF(2))(H(2)O)(8)](3+) units that are bonded to [AlF(6)](3−) anions ([Image: see text] symmetry) and to crystal lattice water mol­ecules via hydrogen bonds. Besides F—H⋯F inter­actions between the dimeric cationic units, O—H⋯F and O—H⋯O hydrogen bonds (both in part bifurcated) are observed.