Stabilization of water structure in ammonium hydrogenphosphate solutions

Abstract

Radio-frequency permittivity and dielectric loss of (NH4)2 HPO4 solutions at 288–308 K in the water permittivity dispersion region (7.5–25 GHz) are studied. Low-frequency electrical conductivities of these solutions are measured, and ionic losses at high frequencies are calculated. The analysis is carried out in terms of the Cole-Cole relaxation model. Static dielectric constants ɛs and the activation times τ and thermodynamic parameters of activation (ΔH ɛ ++ , ΔG ɛ ++ , and TΔS ɛ ++ ) for the dielectric relaxation of the solutions are calculated. The values of ɛs decrease in response to increasing salt concentration at all temperatures. The increasing τ and ΔH ɛ ++ values indicate the stabilization of water structure in solutions where the anion and cation are hydrophilically hydrated.