Infrared spectroscopy in clay mineral studies

Abstract

Infrared absorption by a mineral arises from the vibrations of its constituent atoms, and the frequencies of these vibrations are dependent on the mass of the atoms, the restraining forces of the bonds, and the geometry of the structure. The resultant spectrum of absorption frequencies is a characteristic property of the mineral which can not only serve as a fingerprint for its identification, but also give, in favourable cases, unique information on features of the structure, including the nature of isomorphic substituents, the differentiation of molecular water from constitutional hydroxyl, the degree of regularity of the structure and an indication of the family of minerals to which an unknown mineral is related.