The Structure of Nickel(II) Bromide in Highly Concentrated Aqueous Solution by X-Ray Diffraction Analysis

An X-ray diffraction analysis of the aqueous nickel(II) bromide solutions with the concentrations of 2.004, 4.064, and 4.845 mol dm−3 demonstrated the presence of the complex [NiBr(H2O)5]+. This inner-sphere type complex has interatomic distances of 2.52–2.58 Å for Ni–Br and of 2.04–2.05 Å for Ni–OH2. With an increase in the concentration the average number of the Ni–Br contacts per one Ni2+ ion increased; it was found to be 0.18, 0.47, and 0.68 in the 2.004, 4.064, and 4.845 mol dm−3 solutions, respectively.