X-ray diffraction and structure of NiCl2 aqueous solutions

Abstract

X-ray diffraction data for two aqueous solutions of NiCl₂ are analysed. A model including only nearest-neighbour interactions does not yield theoretical structure functions in full agreement with the experimental results, but satisfactory agreement can be reached by simply adding interactions between the hydrated cation and external water molecules, without considering ion–ion interaction.

Regarding ionic hydration, the mean coordination geometries of Ni²⁺ and Cl^– ions are found to be octahedral with mean distances cation–water (2.05 – 2.06 Å) and anion–water (3.13 – 3.14 Å) in accordance with those already found.