Structure of NaClO4·(H2O)n (n = 1–7) Hydrates and Equilibrium Composition of the NaClO4–H2O System.

Autor: Maiorov, V. D., Kislina, I. S., Tarakanova, E. G.
Předmět:
Zdroj: Journal of Structural Chemistry; Jul2023, Vol. 64 Issue 7, p1165-1175, 11p
Abstrakt: Composition, structure, energy parameters, and areas of existence of hydrate complexes formed in the NaClO4–H2O system are determined by IR spectroscopy and by quantum chemical methods. It is established that the salt dissociate completely up to the 1:11 molar ratio of components, and the solution contains and Na+ ions coordinated by four and six water molecules, respectively. In more concentrated solutions (1:11–1:6), NaClO4·(H2O)6 complexes with a completely filled first hydration shell begin to form. The Na+ ion in these complexes is coordinated by two oxygen atoms of the anion and by four oxygen atoms of water molecules. Solutions with a composition from 1:8.5 to 1:6 contain only partially hydrated NaClO4·(H2O)6 complexes. A further increase of salt concentration (from 1:6 to 1:3.4) leads to the successive formation of NaClO4·(H2O)5, NaClO4·(H2O)4, and NaClO4·(H2O)3 complexes. The changes in the IR spectra of NaClO4–H2O solutions in the regions of fundamental and overtone vibrations of water molecules are quantitatively explained using computational data obtained for the composition and structure of NaClO4·(H2O)n (n = 1–7) hydrates. It is established that anions exhibit nucleophilic assistance in acid-catalyzed hydrolysis reactions only when they are part of the composition of NaClO4·(H2O)n (n = 3–6) complexes. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index