[C7H10N][In3Se5]: a layered selenide with two indium coordination environments

A new layered indium selenide, [C(7)H(10)N][In(3)Se(5)] (1), has been prepared solvothermally using 3,5-dimethylpyridine as a solvent and structure-directing agent. This material, which was characterized by single-crystal and powder X-ray diffraction, thermogravimetric analysis, UV-vis diffuse-reflectance spectroscopy, IR spectroscopy, and elemental analysis, crystallizes in the monoclinic space group P2(1)/c [a = 3.9990(4) A, b = 16.7858(15) A, c = 23.930(2) A, and β = 94.728(4)°]. The crystal structure of 1 contains anionic layers of stoichiometry [In(3)Se(5)](-) in which indium atoms with octahedral and tetrahedral coordination coexist. The [In(3)Se(5)](-) layers are interspaced by monoprotonated 3,5-dimethylpyridinium cations. A closely related material, [C(7)H(10)N][In(3)Se(5)] (2), was obtained when using 2,6-dimethylpyridine instead of 3,5-dimethylpyridine.