EPR investigation of two types of Syrian's natural zeolites

Two different samples of natural zeolite have been investigated by X-band electron paramagnetic resonance (EPR) spectroscopy. The observed EPR spectra are typical to those observed for Fe3+ and Mn2+ ions. The lines, related to the iron, are observed, respectively at g approximate to 4.3 and g approximate to 2. The observed six lines, at g approximate to 2, are the hyperfine structure due to the Mn2+ ions. The simulation of the experimental EPR spectra suggests that both of the manganese and the iron are present in more one site. The temperature dependence of the EPR spectra has been also investigated. The nature of the different sites involved in the EPR absorption is discussed. (C) 2004 Elsevier Ltd. All rights reserved.