The structure of hydration shells was studied for the ionic constituents of NaBr, NaNO3, and NaCl. The thermal stability of the nearest environment of the Na+ cation was estimated by measuring the relaxation rates of deuterium nuclei in NaNO3-D2O solutions. A hypothesis was suggested according to which changes in the hydration of Cl- anions influenced the amount of "free" water and the occurrence of energy reactions in it. Copyright © 2005 by Pleiades Publishing, Inc.