The Crystal Structure of trans-Dibromo-bisethylenediamine-cobalt(III) Bromide Hydrobromide Dihydrate

Abstract

Abstract The structure of trans-dibromo-bisethylenediamine cobalt(III) bromide hydrobromide dihydrate has been determined by X-ray analysis. [Co en2Br2]Br·HBr·2H2O is monoclinic, a=10.98, b=8.18, c=9.46 Å, and β=113.2°, space group P21⁄c, two formula units in the cell. The structure consists of [Co en2Br2]+, [H2O···H···H2O]+ and Br−, and is isotype with [Co en2Cl2]Cl·HCl·2H2O. The complex ion has a center of symmetry. Two enantiomorphous ethylenediamine molecules, taking “gauche” configration, are coordinated to a cobalt atom. A cobalt atom is surrounded in a square coplanar configuration by four nitrogen atoms at distances 2.0 Å, and on a line approximately perpendicular to the plane of nitrogen atoms are two bromine atoms at distances 2.44 Å. The marked dichroism of the crystal is explainable in terms of the characteristic features in the arrangement of the complex ions in the crystal.