Nuclear magnetic resonance and thermal studies of concentrated aqueous solutions of lithium chloride

Abstract

The nuclear spin relaxation times, T₁ and T₂, of ⁷Li nuclear magnetic resonance have been investigated over a wide range of temperatures in 14 mol kg^–1 aqueous lithium chloride solution, whose thermal behaviour was examined with differential thermal analysis. The relaxation is mainly attributed to dipolar coupling between water protons and lithium ions, and T₁ and T₂ at temperatures higher than the glass transition point are governed by the translational motion of the hydrated lithium ions. The activation parameters of the motion were found to be E_a= 33.5 ± 0.8 kJ mol^–1, τ₀=(1.2 ± 0.5)× 10^–17 s. The E_a values are similar to those for molecular self-diffusion in a plastic-crystalline phase of globular molecules.