Redetermination of dipotassium trichloridostannate(II) chloride monohydrate

Abstract

The title compound, K2[SnCl3]Cl·H 2O, is the prototype of some isostructural compounds of composition M 2[SnX 3]X·H2O (M = large monovalent cation; X = halogen). In comparison with a previous study based on photographic data [Kamenar & Grdenić (1962). J. Inorg. Nucl. Chem. 24, 1039-1045], its crystal structure has now been redetermined using CCD-based data in order to gain more accurate values for bond lengths and angles within the [SnCl3] - anion and to locate the H atoms. The [SnCl3]- anion has a trigonal-pyramidal shape and exhibits crystallographic mirror symmetry. With the exception of the K+ ion which is located on a general position, all other atoms are situated on crystallographic mirror planes. The coordination polyhedron of the cation may be described by means of nine atoms in the form of a monocapped square antiprism with seven typical K - Cl/O distances and two additional atoms at considerably longer distances. The positions of the H atoms of the water molecule (also lying on a crystallographic mirror plane) could be determined and confirm the existence of a bifurcated O - H⋯Cl hydrogen bond to neighbouring Cl atoms.