EXAFS studies of strong electrolytic solutions

Extended x-ray absorption fine structure measurements are reported for aqueous solutions of CuBr2, ZnBr2, CuCl2, NiCl2, and NiBr2 at various concentrations. It is shown that, for highly concentrated solutions of CuBr2, ZnBr2, and CuCl2, some local order, resembling that of the corresponding crystals, exists. When the concentration decreases, this order partly remains, while the hydration increases. In contrast to this behavior, SrBr2 does not show the existence of any bonding, and it is difficult to make conclusions in the case of NiCl2 and NiBr2 solutions. The temperature dependence of the EXAFS spectra of CuBr2 and ZnBr2 is presented also; some change in the low energy region occurs between 45 and 60°C for CuBr2 solutions.