Infrared spectroscopy interlayer water

Spectroscopic methods for hydration of ions were reviewed for structural aspects and dynamic aspects of ionic hydration by Ohtaki and Radnai (150). They discussed X-ray diffraction, neutron diffraction, electron diffraction, small-angle X-ray (SAXS) and neutron-scattering (SANS), quasi-elastic neutron-scattering (QENS) methods, extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES) spectroscopies, nuclear magnetic resonance (NMR), Mdssbauer, infrared (IR), Raman, and Raleigh-Brillouin spectroscopies. The clay interlayer molecular modeling where clay surface is interfaced with aqueous solution also includes ions that are also solvated by interlayer water. 

Using infrared spectroscopy, Fripiat et al. [1960] have shown that some interlayer water molecules are trapped in the lattice of a South African vermiculite during contraction by heat treatment and that dehydroxylation starts before the final removal of the interlayer water. Warshaw et al. [1960] examined the X-ray diffraction patterns of a vermiculite from Westtown, Pennsylvania, after heating at various temperatures for periods of 11 to 16 hr, but made no attempt at a structural interpretation of their data. After heating at 120°C, they observed that the 14.3 A basal reflection was displaced to 11.6 A at 270°C, a broad band consisting of peaks at 12.6 and 10.8 A was found at 400° and 475°C, the broad band consisted of peaks at 10.2 and 8.7 A and at 500°C, the broad band was centered on 9.6 A with a slight shoulder at 8.7 A. 

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