Crystal and Molecular Structure of 1,2,4-Triazolium Chloride and its Salt with Antimony Trichloride - Bis(1,2,4-triazolium) pentachloroantimonate(III)-1,2,4-triazolium Chloride

The structures of 1,2,4-triazolium chloride (C2H4N3)Cl and its derivative with antimony trichloride (C2H4N3)2[SbCl5] ÿ (C2H4N3)Cl containing unsubstituted 1,2,4-triazolium cations were determined. (C2H4N3)Cl crystallizes in the monoclinic system, space group P21/n with the unit cell dimensions at 86 K: a = 9.425(2), b = 8.557(2), c = 11.158(2) Å, þ = 95.87(3); V = 895.2(3) Å3,Z= 8,dc = 1.566,dm = 1.56(2) gÿcmþ3. At room temperature, crystals of (C2H4N3)2[SbCl5] ÿ (C2H4N3)Cl are orthorhombic, space group P212121, a = 8.318(2), b = 11.381(2), c = 19.931(4) Å, V = 1886.8(7) Å3, Z = 4, dc = 1.917, dm = 1.91(2) gÿcmþ3. In both crystals the 1,2,4-triazole rings are planar. The anionic sublattice of (C2H4N3)2[SbCl5]ÿ(C2H4N3)Cl consists of polymeric [SbCl5]n 2þ zig-zag chains composed of distorted [SbCl6] octahedra connected via their vertices and the single Cl anions. The cavities between the inorganic chains are filled by 1,2,4-triazolium cations. The nature of the distortion of the [SbCl6] polyhedra has been studied by examining correlations between the Sb-Cl bond lengths and the strength of hydrogen bonds, which join the anionic sublattice and the organic cations. This study confirms that the deformation of the [SbCl6] octahedra is caused by hydrogen bonds.