Hydrogen-deuterium exchange in clays and problems in the assignments of infrared frequencies

In spite of the considerable interest and work with infrared absorption spec-tra not much reliable correlation has as yet been made between these spectra and other properties of the clays. Where generalizations have been made they have been based on a few samples and not the best-quality patterns. An ex-amination of the "hydroxyl region " of the infrared spectra of montmorillonites in various states of dehydration, kaolin family minerals, brucite, gibbsite and other hydroxides and clays was made on the Perkin-Elmer model 21 double-beam spectrometer, employing samples mixed with KBr and pressed into discs. Resolution of several maxima in the hydroxyl region of powder spectra of brucite (2.33, 2.47, 2.68, 2.8, 3.03, 3.4?, and 3.96 microns) was obtained. Mg (OD) 2 synthesized under high temperature and D20 pressure revealed a sim-ilar spectrum, with maxima present at higher wave lengths which are multiples (1.37 times) of the corresponding Mg (OH)2 wave length (3.18, 3.35, 3.65, 3.84, 4.08, and 4.2 microns) with a trace of the 2.68 micron (OH)- absorption maximum. Resolution of three strong maxima at 2.673, 2.708, and 2.732 mi