Study by ESR and Optical Spectroscopy of Transition-metal Ions in Zeolites and of Their Complexes with Adsorbed Molecules

Studies by ESR and optical spectroscopy of zeolites containing transition-metal ions are reviewed. The locations of transition-element ions introduced into zeolites of various types by cation exchange and identified by these techniques are generalised. It is shown that these methods give useful information on the accessibility of the ions by adsorbed molecules and on the electronic structure of the complexes formed by the interaction between adsorbed molecules and transition-metal ions. The properties of these complexes are discussed. 122 references.