New polymolecular bismuth monohalides.: Synthesis and crystal structures of Bi4BrxI4-x (x=1, 2, or 3)

New mixed bismuth monolialides Bi4BrxI4-x, (X = 1, 2, or 3) were prepared for the first time by the reactions of bismuth metal with bismuth trilialides taken in stoichiometric amounts. Their crystal structures were established by single-crystal X-ray diffraction analysis. The Bi4Br3I and Bi4BrI3 compounds are isostructural and crystallize in the orthorhombic system, and Bi4Br2I2 crystallizes in the monochnic system. The crystal structures of all three phases contain one-dimensionally infinite molecular chains consisting of the \Bi4X4\ fragments whose structures are identical with those of the individual Bi4I4 and Bi4Br4 molecules. The molecules are packed in layers. Different packing modes of the layers were found for different bismuth monolialides. The Bi4CII3 Compound, which is apparently structurally similar to Bi4Br3I and Bi4BrI3, was also prepared.