Ba₃[Sn(OH)₆][SeO₄]₂·3H₂O, a hydrated 1:2 double salt of barium hexahydroxidostannate(IV) and barium selenate(VI)

Abstract

Single crystals of tribarium hexahydroxidostannate(IV) bis[selenate(VI)] trihydrate, Ba 3 H 12 O 17 Se 2 Sn or Ba 3 [Sn(OH) 6 ][SeO 4 ] 2 ·3H 2 O, prepared from solid BaSnO 3 and aqueous Na 2 [SeO 4 ] solutions have hexagonal ( P 6 3 ) symmetry. The structure consists of four different primary building units: a hexahydroxidostannate(IV) ion, two different selenate(VI) ions, all three of point group symmetry C 3 , and a mono-capped {BaO 9 }-square antiprism of point group symmetry C 1 . The secondary building units result from three of the barium coordination polyhedra linked together via common edges. While one of the two tetrahedral voids formed from these trimeric units is filled by one bidentate, chelating μ 2 -selenate ion, the other one remains unoccupied as the corresponding second selenate ion only acts as a monodentate, μ 1 -ligand. SBUs are completed by hexahydroxidostannate(IV) ions sharing adjacent edges on the uncapped faces of the three, mono-capped square antiprisms. These SBUs are arranged into layers via common edges on the uncapped, square faces of the {BaO 9 } coordination polyhedra in a way that the hexahydroxidostannate(IV) ions act as linkage between two neighboring layers.