Proton Resonance Shifts in Alkali Halide Solutions

Abstract

Proton magnetic resonance shifts in alkali halide solutions with respect to distilled water have been measured as a function of ionic charge, radius, and concentration. The shifts are linear with concentration up to a certain concentration depending on the salt. In this linear range, the shifts due to each ion are independent of one another and can be obtained by arbitrarily assuming the shift of the chloride ion to be zero. The ionic shifts so obtained are linear with the ionic crystal radius for anions and cations at a given salt concentration. Results are presented showing that the time‐averaged packing of the ions is closer than if they were arranged on a cubic lattice and that the ionic effects on the proton shielding do not extend past nearest‐neighbor water molecules.