Structure of ZnZrF6 center dot nH(2)O (n=6-2) and ZnZrF6 crystallohydrates according to vibrational spectroscopy data

摘要

Fluoridezirconate crystallohydrates ZnZrF6 center dot nH(2)O (n = 6-2) and anhydrous ZnZrF6 are investigated by vibrational spectroscopy and thermography. The influence of the hydrate number on the structure of the cationic and anionic sublattices of the crystallohydrates is studied. The changes in the strength of HOH center dot center dot center dot F and HOH center dot center dot center dot O hydrogen bonds of coordinated and outer-sphere water molecules occurring with variations in the hydrate number are determined by changes in the IR spectra. The IR spectra of ZnZrF6 center dot nH(2)O (n =6, 4) compounds, which have isolated complex anions [ZrF6](2-) in their structure, revealed a band with two peaks in the range of 3470-3430 cm(-1), which corresponds to stretching vibrations of coordinated water molecules. The spectra of ZnZrF6 center dot nH(2)O (n = 5, 3, 2, 1) crystallohydrates with a polymeric structure show a high-frequency shift of this band, which corresponds to weakening of hydrogen bonds. The vibrations of crystallization water molecules involved in the network of strong O-H center dot center dot center dot F and O-H center dot center dot center dot O hydrogen bonds manifest themselves in the spectra of ZnZrF6 center dot nH(2)O (n =5, 3) crystallohydrates by broad structureless bands in the region of stretching, bending, and libration vibrations.