Ultrasonic investigation of ion-solvent interactions in aqueous and non-aqueous solutions of transition and inner transition metal ions

Ultrasonic velocities (u) and densities (p) have been measured for aqueous and dimethyl sulphoxide (DMSO) solutions of manganous(II) sulphate, cobalt(II) chloride, nickel(II) sulphate, ferrous sulphate, copper(II) sulphate, zinc(II) sulphate, lanthanum(III) nitrate, cerium(IV) nitrate, uranyl nitrate and thorium(IV) nitrate in a wide range of concentrations at 303 K. Acoustical parameters, such as, adiabatic compressibility (β), free length (Lf) and solvation number (S,,) have been computed to assess the ion-solvent interaction in these solutions. It is found that the ion-solvent interactions depend on concentration, ionic size and nature of metal ion. The transition and inner transition metal ions behave as structure breaker for the associated clusters of water molecules, especially in dilute solution, as evidenced from the trend in the solvation number with molarity. The strength of ion-dipole interaction in aqueous solution of the metal ion is also concentration dependent, which is also investigated in the present work.