Original scientific paper

Solvation of Potassium Ion in Water and in Water-Dimethyl Sulfoxide Mixtures

Warren L. Reynolds ; University of Minnesota, Chemistry Department, 207 Pleasant Street, S. E., Minneapolis, Minnesota 55455, U. S. A.
Steven Davis ; University of Minnesota, Chemistry Department, 207 Pleasant Street, S. E., Minneapolis, Minnesota 55455, U. S. A.
Mira Glavaš ; Prirodno-Matematički Fakultet, University of Sarajevo, Sarajevo, Yugoslavia

Abstract

A model has been obtained for the solvated K+ ion in the solvents named in the title using a modified Covington approach.
The solvation number an this model was determined to be 14 of which 6 molecules were found to be unique and which were assigned to the inner solvation shell. These 6 inner solvent molecules were unique in that the stepwise formation constants for replacement of water by dimethyl sulfoxide were found to be given by the first stepwise formation constant Ki, and the statistical factors in the first six stepwise formation constants.
The remaining eight solvent molecules were assigned to an outer solvation shell. Their stepwise formation constants for replacement of water by dimethyl sulfoxide were given by Ki, statistical factors and a power of a parameter k which determines changes in the free energy of the stepwise formation reaction exclusive of contributions from changing statistical factors.
The stepwise formation constants (Ko to Ku inclusive) and the
free energies of transfer of each of the 15 specie KWi4-iDi+
(i = 0,l,...,14) were used to compare the calculated free energies of transfer of K+ from water (W) to water (W) — dimethyl sulfoxide (D) mixtures with the experimental values. The agreement was satisfactory.

Keywords

Hrčak ID:

137398

URI

https://hrcak.srce.hr/137398

Publication date:

10.8.1990.

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