Investigation of the hydration phenomenon in 3-1 electrolyte solutions

Abstract

The apparent molar compressibilities j _K of aqueous 3-1 electrolyte solutions have been determined from ultrasound velocity and density measurements at 20^o C. The values of j _K have been extrapolated to infinite dilution, and the total hydration numbers Zo for investigated solutions were estimated from the data j _K⁰. A correlation between the hydration and the atomic number of elements of the Periodic Table are discussed. Non monotonic variation of the hydration number was obtained for lanthanide nitrate solutions across the series. The lower hydration numbers values for the nitrate solutions, compared with chloride and bromide, are interpreted by the formation of inner sphere complexes [LnNO₃]²⁺