VIBRATIONAL SPECTRA OF HEXAAQUA COMPLEXES .5. THE WATER BENDING BANDS IN THE INFRARED SPECTRA OF TUTON SALTS

摘要

Multiple overlapped bands forming a broad complex which extends over several hundreds of reciprocal centimeters appear in the water bending region of the spectra of Tuton salts whose general formula is (M2MII)-M-1(XY4)(2) . 6H(2)O. The essential characteristics of the complex persist when one univalent cation is replaced by another, when the nature of the divalent cation is changed or when a sulfate salt is compared with an analogous selenate compound. This shows that the feature is related to water vibrations only and this is supported by its behaviour on deuteration. Since neither the number of components nor the spread of their frequencies can-be attributed solely to the fundamental vibrations of different types of water molecules, anharmonic couplings of the delta(HOH) modes with second-order transitions must be responsible for the observed spectral picture. (C) 1997 Elsevier Science B.V. [References: 11]