Temperature Features of Hydration of Singly-Charged Ions as Studied in A Diffusion NMR Experiment

Abstract

© 2020, Springer-Verlag GmbH Austria, part of Springer Nature. The concentration dependences of the self-diffusion coefficients of water molecules in water solutions of a series of 1–1 electrolytes at different temperatures determined using nuclear magnetic resonance (NMR) with a magnetic field gradient are analyzed. The relevant results show that the hydration sign for Cs+, I−, Rb+, Br−, K+, and Cl− ions changes at temperatures characteristic for each ion. These characteristic temperatures are determined for the ions and KI, KBr, KCl, CsF, LiI, KF, LiCl, NaCl, RbCl, and Li2SO4 water solutions. The temperature dependence of the τ/ τ1i ratio of the lifetime of water molecules in the structure of bulk water τ to their lifetime in the structure of hydrated shells τ1i of Cs+, I−, Rb+, Br−, Cl−, K+, Na+, F−, and Li+ ions (i) is studied.