Structural parameters of concentrated aqueous solutions of LiCl under extreme conditions, as calculated by the method of integral equations. Effect of temperature

Abstract

Peculiarities of structure formation of aqueous LiCl solutions at different salt : water molar ratios (LiCl : n H2O, n = 3.15, 8.05, 14.90) under conditions of isobaric heating (p = 100 bar, T = 298, 323—523 K, ΔT = 50 K) were studied by the method of integral equations. Heating of LiCl : 14.90H2O solution was found to lead to disappearance of tetrahedral ordering of solvent molecules, appreciable weakening of the coordination abilities of both ions, and to an increase of the number of contact ion pairs and a decrease of the number of solvent-separated ion pairs. For the LiCl : 8.05H2O system, the tetrahedral structure of the solvent disappears at a lower temperature and heating has a less pronounced effect on the coordination and associative abilities of the ions. In the LiCl : 3.15H2O solution, tetrahedral ordering of the solvent molecules disappears at 298 K and the number of contact ion pairs decreases as temperature increases. Other structural changes in this system upon heating are similar to those found for the LiCl : 14.90H2O and LiCl : 8.05H2O solutions.