A Relation between the Lyotropic Series and Free Energies

Abstract

MANY physical-chemical properties and reactions of solutions, such as hydration of ions, flocculation of sols, swelling and liquefaction of gels and surface tensions, are influenced by the presence of ions the order of effectiveness of which is often expressed as the lyotropic or Hofmeister series. The order is not invariable and, whilst factors such as hydrogen ion concentration, valency and activity are of much importance¹, the series appears still to embody some fundamental property. It is of much interest, therefore, that the order of the anions arranged in the lyotropic series runs closely parallel with the order of the (Gibbsian) standard free energies of formation from their elements (see accompanying table).