Theoretical Study on Microhydration of Bisulfate Ions [HSO4− (H2O)n] n = 0−3,5

Abstract

Micro-hydration studies of electropositive and electronegative ions are especially important while interpreting ionic solvation mechanisms, hydrated ground state electronic structures, and energetic properties at atomic levels. The micro-hydrated hetero-atom centered ions such as sulfur-centered HSO₄⁻have always fascinated experimental and theoretical chemists due to their excessive presence in many electrolytic solutions, various day-to-day edible foods and drugs, sea water as well as in naturally occurring oligoelements. Despite their high abundances, usefulness and essentiality for the growth and survival of animal and vegetal life, in depth theoretical studies concentrated on their hydration structures and electronic stabilization in the aqueous type solutions are very limited. This research work is aimed to probe deep into the molecular-level of HSO₄⁻ ion hydration by employing ab initio type theoretical model. The noteworthy findings are that the central bisulfate H-atom always forms an H-bond to the nearest H₂O molecule, and whenever the degree of solvation n < 3 H₂O, the bisulfate O-atoms make two or more H-bonds with H₂O; but when n ³ 3 H₂O, these O-atomsform one to two H-bonds with H₂O that is further linked to another H₂O by H-bond. The significance and novelty of this study lies in illuminating most of the physicochemical properties of HSO₄⁻ ions in any inorganic bisulfate aqueous type solutions, as well as in modelling their hydrated systems while exploring solvation dynamics in bulk solutions.