Structural Characteristics of Concentrated Aqueous Solutions of Lithium Bromide under Extreme Conditions, Evaluated by the Method of Integral Equations

Author： Gribkov A. A. Fedotova M. V. Trostin V. N.

Publisher： MAIK Nauka/Interperiodica

ISSN： 1070-3632

Source： Russian Journal of General Chemistry, Vol.74, Iss.7, 2004-07, pp. : 1005-1015

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Abstract

The influence of temperature (T 298-623 K) at constant pressure (P 200 bar) on the structure of aqueous solutions LiBr:nH₂O (n = 15, 8, 4) was studied using the method of integral equations. In the less concentrated solutions, heating results in disappearance of the tetrahedral ordering of solvent molecules; in the more concentrated soltion, this ordering is lacking even at 298 K. In the systems LiBr:15H₂O and LiBr:8H₂O, with heating, the hydrogen bonding and the coordinating power of the cation get considerably weakened, the amount of contact ion pairs grows, and the amount of hydration-separated ion pairs decreases. On heating, the H bonds between the anion and water molecules of its first coordination sphere are largely ruptured. At the same time, the structuring of the LiBr:4H₂O solution under extreme conditions has certain specific features: with increasing temperature, the intermolecular hydrogen bonding becomes stronger, and the amount of hydration-separated ion pairs increases.