The partial molar volume and area of solvated ions and some aspects of partial charge transfer
- Landstorfer, Manuel
2010 Mathematics Subject Classification
- 78A57 35Q35 34B15
2008 Physics and Astronomy Classification Scheme
- 82.45.Gj, 68.43.-h, 68.35.Md
- Double layer, adsorption, solvation, surface mixture theory, partial charge, transfer, electrode/electrolyte enterface
The double layer capacity is one of the central quantities in theoretical and experimental electrochemistry of metal/electrolyte interfaces. It turns out that the capacity is related to two central thermodynamic quantities, i.e. the partial molar volume of an ionic constituent and the partial molar area of the respective adsorbate. Since ions in solution (or on the surface) accumulated solvent molecules in their solvation shell, the partial molar volume and area are effected by this phenomena. In this work we discuss several aspects of the relationship between the molar volume and area of an ion, the solvation number and the charge number. In addition, we account for partial charge transfer on the metal surface which explains naturally the difference of the capacity maxima between ceF- and ceClO4- on silver. We provide simple yet validated analytical expressions for the partial molar volume and area of multi-valent ions and parameter values for aqueous solutions.