Preferential Solvation of Single Ions: The PH₄ASPH₄B Assumption for Single Ion Thermodynamics in Mixed Dimethylsulfoxide‐Water Solvents

The paper presents a study of the Ph 4 AsPh 4 B assumption as for verification of its plausibility for the determination of thermodynamic quantities of single ions in mixed dimethylsulfoxide (DMSO)‐water solvents. For discussion the solvation energy is considered as a composite of electrostatic and neutral components. The neutral components are replaced by experimental data of Ph 4 Ge and Ph 4 C which are proved to be equal, of their size and structure, to the reference cation and anion. The electrostatic components are obtained by calculation according to the theory in the literature. The results of the present investigation provide the conclusion that an assymmetric partition is preferred to an equal partition practiced in the literature. Based on the study, the standard free energies of transfer for single ions, Ph 4 As + , Ph 4 B, Cs + and I − , are determined and for others, H + , Li + , Na + , K + , Rb + , Cl − and Br − evaluated from the data of salts known in the literature. Discussion is elaborated with solvation properties of individual ions.