Composition of the first coordination sphere of Ni2+ in concentrated aqueous NiCl2 and NiBr2 solutions. Part 1.—Application of solvent nuclear magnetic relaxation

Abstract

Proton and deuteron relaxation rates in aqueous solutions (H₂O and D₂O) of NiX₂(X = Cl, Br) in the concentration range 0 < c^*⩽ 4 mol kg^–1 are reported. The deuteron relaxation rates were found to depend substantially linearly upon the NiX₂ concentration. Comparison of the concentration dependences of the deuteron relaxation rate observed in these solutions with those in diamagnetic MgX₂ solutions yielded information about the composition of the first hydration sphere of Ni²⁺. Some additional measurements with solutions containing only small amounts of Ni²⁺ in concentrated KX solutions were also performed.