Redetermination of dipotassium trichloridostannate(II) chloride monohydrate

Abstract

The title compound, K2[SnCl3]Cl·H2O, is the prototype of some isostructural compounds of compositionM2[SnX3]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.