[Cu2(HF2)(H2O)8][FeF6]•2H2O

The title compound, octaaqua(hydrogenfluorido) dicopper(II) hexafluoridoferrate(III) dihydrate, was synthesized under hydrothermal conditions. The Cu atom is coordinated by one F and five O atoms within a highly distorted octahedron, forming dimeric [Cu-2(H2O)(8)HF2](3+) units by edge sharing. These units are hydrogen bonded to [FeF6](3-) anions and to an interstitial water molecule. The former feature Fe3+ on a special position ((1) over bar). The dimeric copper units are linked to adjacent dimers by F-H center dot center dot center dot F hydrogen bonds. Additional O-H center dot center dot center dot O and O-H center dot center dot center dot F hydrogen bonds help to consolidate the crystal packing.