Abstract
Concentrated aqueous chloride solutions containing equal amounts of transition metal ions of almost equal ionic radii (Co2+, Ni2+ and Cu2+) have been examined by the x‐ray diffraction technique. CoCl2 and Nicl2 solutions show distribution curves very similar to each other which leads to the conclusion that the same dominant species should occur in both systems. The analysis of the structure functions can be achieved by considering M(H2O)2+6 (M=Co2+, Ni2+) as the dominant species although indication is given in favor of the presence of about 50% of the M(H2O)5Cl+ complex [and the rest M(H2O)2+6] in both solutions. The distribution curve of CuCl2 solution is markedly different from those of cobalt and nickel. Equatorial positions, in the distorted octahedral copper coordination are, on the average, occupied by about 2.8 water molecules (at 1.95 Å) and about 1.2 chloride ions (at 2.25 Å). Occupancy of the axial copper positions is discussed, though no unique conclusion can be obtained with respect to this point from the scattering data.