Partial molar compressibility of ions in aqueous solutions of some rare Earth chlorides and nitrates

Abstract

The individual ionic contributions in the partial molar compressibility K₂⁰ of rare earth chlorides and nitrates in aqueous solutions are analysed. The values of ` K<sub>2</sub><sup>0</sup> for rare earth nitrates in aqueous solutions showed that ion-solvent interaction cannot be explained simply by electrostatic field theory. The lanthanide nitrates form inner sphere complexes and amount of these complexes depends nonlinear across the series. The individual partial molar compressibility ` K⁰_Me³⁺ for Sm³⁺, Gd³⁺, Tb³⁺, Lu³⁺ cations in aqueous chloride solutions can be accounted only in terms of electrostrictive effects. The individual hydration numbers for these cations were calculated. The hydration number of chloride ion Z⁰Cl^-1=2 was estimated and no inner sphere complexation exists in dilute rare earth chloride solutions.