Structure of chloroantimonates(III) with an imidazolium cation: (C 3H 5N 2)[SbCl 4] and (C 3H 5N 2) 2[SbCl 5

Abstract

Two different chloroantimonates(III) with an imidazolium cation have been synthesized by the reaction of antimony trichloride and imidazole in an aqueous solution of hydrochloric acid. The crystals of (C 3H 5N 2)[SbCl 4] are monoclinic, space group C2/ c, while (C 3H 5N 2) 2[SbCl 5] crystallizes in the orthorhombic system, space group Pbcn. Both crystals are built of one dimensional zig-zag chains composed of [SbCl 6] 3− octahedra connected by edges and corners, respectively. The cavities between inorganic chains are filled by imidazolium cations. In both structures, one crystallographically independent imidazolium cation is rotationally disordered, and the positions of all atoms are split between two sites. The organic cations are joined to inorganic sublattices by N–H⋯Cl and C–H⋯Cl hydrogen bonds. The [SbCl 6] 3− units are significantly distorted, with Sb–Cl bond lengths between 2.372(1) and 3.228(1) Å. The largest differences were observed between lengths to terminal and oppositely located bridging Cl atoms. The maximum differences in Sb–Cl bond lengths within the same [SbCl 6] 3− octahedron are 0.856(2) and 0.597(2) Å in (C 3H 5N 2)[SbCl 4] and (C 3H 5N 2) 2[SbCl 5] crystals, respectively. Analysis of the intermolecular interactions between inorganic and organic sublattices has shown that the additional deformation of the [SbCl 6] 3− octahedra is caused by the N–H⋯Cl and C–H⋯Cl hydrogen bonds.