Strontium hexa-fluorido-stannate(IV) dihydrate.

Colourless, needle-like single crystals of the title compound, Sr[SnF6]·2H2O, were grown from stoichiometric amounts of SrF2 and SnF4 in boiling water. The compound is isostructural with the corresponding hexa-fluorido-iridate(IV) and features a nearly undistorted octa-hedral [SnF6]2- anion with C 1 point-group symmetry, as well as an Sr2+ ion in a distorted, square-anti-prismatic coordination environment. The resulting [SrF5(H2O)3] coordination polyhedra share an edge via two water mol-ecules to form centrosymmetric dimers. As the strength of the O-H⋯F and O-H⋯O hydrogen bonds is less pronounced, the crystal packing is dominated by μ 2-F atoms between anions and cations.