Application of luminescence methods in the study of the structure of aqueous electrolyte solutions

Luminescence methods have been applied to the study of solutions of concent rated aqueous electrolytes of LiCl, CaCl2, LiBr, CsCl et al. with addition to those of LnCl(3), NICh(2), MnCl2. The rate constants of energy transfer from Tb(III) ions to Er(III), Ni(II), Mn(II) were measured in solutions of different electrolytes. So as the energy transfer rate depends on the dista nce between the energy donor and acceptor, it can be shown from this study, that the labile nanostructures of lanthanide ions are formed in concentrat ed aqueous solutions of LiCl and to a lesser degree in solutions of CaCl2. The concentration of lanthanide ions in labile nanostructures is close to t hat of a saturated aqueous solution of LnCl(2), The labile nanostructures c onsist of no less than several tens of lanthanide ions which exchange with ions of the solution during the time of less than one Cls The mixed labile nanostructures of lanthanide and Ni(II) or Mn(II) ions are also formed in c oncentrated LiCl solutions, but they are less stable. The dependence of lab ile nanostructure stability on temperature and on the addition to the elect rolyte solution of other multicharge cations was also studied. The nature o f the phenomenon of the labile nanostructure formation is discussed. (C) 20 01 Elsevier Science B.V. All rights reserved.