Abstract: The present review describes the mathematical apparatus used to calculate general parameters that characterise electrotransport behaviour of ions in solutions. On this basis, values of some parameters featuring common inorganic ions have been estimated. The structure of the solutions and the influence of different ions on the structure of the solvents are interpreted in the light of Samoylov’s theory of positive and negative hydration of ions. By using the empirical electrophylic and nucleophylic orders of ions of Pearson and Klopman’s generalised perturbation theory of chemical reactivity the observed tendencies in the change of solubility products of some inorganic compounds are explained. The presented mathematical apparatus can be used to characterise non-aqueous and mixed solutions.