Effect of hydrochloric acid on the mean solute species in copper(II) chloride/hydrochloric acid solutions

In the concentrated solutions of CuCl₂/HCl/H₂O examined in this study, Cu²⁺ has tetragonally distorted octahedral coordination on the average. In these solutions of ca. 2 molar concentration, solute association does not appear to be an important solution parameter. In all of the solutions, the linear Cl_axCuCl_ax network remains intact upon dissolution of anhydrous copper(II) chloride. Ligand occupation of the equatorial coordination sites apparently is dependent upon the chloride/copper and/or the water/chloride stoichiometric ratios in each solution. The Cu-ligand bond distances are calculated to be: CuO_eq, 1·95 Å; CuCl_eq, 2·35 Å; and CuCl_ax, 2·8 Å. The latter two distances are significantly different than those calculated for the highly associated solute species found in aqueous solutions of CuCl₂[1].