Face-Shared Octahedral Dimer In2O7S2 in the Non-Centrosymmetric Barium Indiumsilicate Oxysulfide Ba2In2Si3O10S.

The first indiumsilicate oxysulfide Ba2In2Si3O10S ( 1) was obtained by an alkali polychalcogenide flux method through a high-temperature solid-state reaction. It crystallizes in the non-centrosymmetric space group Pca21 (No. 29), with a = 23.060(6), b = 5.2954(6), c = 8.779(2) Å, and Z = 4. Its three-dimensional (3D) framework is constructed from one-dimensional (1D) infinite ∞1[In2O7S2/2] double octahedral chains bridged by corner-sharing Si tetrahedral trimers [Si3O10]8-, yielding a 3D framework with the channels filled with Ba2+ cations along the b direction. It is unprecedented in that the two distorted indium octahedra in 1 face-share to form a [In2O7S2] dimer in indium oxides and oxide chalcogenides. [ABSTRACT FROM AUTHOR]