Primary- and secondary-octahedral distortion factors in bis(1,4-H2-1,2,4-triazolium) pentabromidoantimonate(III)–1,4-H2-1,2,4-triazolium bromide

Abstract

The analysis of octahedral distortion in the structure of inorganic–organic (C2H4N3)2[SbBr5]·(C2H4N3)Br (BTPTB) bromidoantimonate(III) determined at 295 and 85K, supported by the Hirshfeld surface analysis and the data retrieved from the Cambridge Structural Database, is presented. The anionic substructure of BTPTB is built from distorted [SbBr6]3− octahedra that are connected by the cis corners forming polymeric one-dimensional [{SbBr5}n]2n− zig-zag chains running parallel to the a axis and isolated Br− ions. The organic substructure consists of the fully ordered 1,4-H2-1,2,4-triazolium cations. The oppositely charged substructures are linked by the system of N(C)–H⋯Br hydrogen bonds causing further distortion of [SbBr6]3− octahedra. The comparison of octahedral geometry and distortions found in the structure of BTPTB determined at room and low temperature, to access the attractive nature of hydrogen bonds, clearly shows that hydrogen bond interactions are responsible for secondary distortion of octahedra and the observed deviations are comparable to primary distortion that is caused by the intrinsic interactions within inorganic substructure. Furthermore, a comparison of packing features and interactions in BTPTB with those in the structure of organic 1,4-H2-1,2,4-triazolium bromide, (C2H4N3)Br (TB), also determined at 295 and 85K, confirms the importance and hierarchy of factors that are responsible for polyhedral distortion.