Fe was introduced in mordenite zeolite by means of ion exchange either in solid or in liquid state. The iron loading (50-200 wt%), iron precursor (FeSO4.7H(2)O and FeCl3), and mordenite starting material (NH4M, HM, and NaM) were varied during the exchange processes. The Fe species were characterized by N-2 adsorption measurements as well as by XRD and Mossbauer spectroscopies. The Fe-mordenite samples prepared by liquid-state ion exchange attained remarkable Fe dispersion and surface areas higher than those of the parent. It was found that Fe3+ ions, which substituted the framework Al and accordingly occupied tetrahedral sites, were decreased with Fe loadings with concomitant increase in Fe3+-occupied octahedral sites. The latter sites disappeared at 20 K to provoke the superparamagnetic alpha-Fe2O3 in different particles size. The acid leaching (0.1 M HCl, 333 K, 3 h) of the samples showed the disappearance of the most highly distorted extra-framework Fe3+ species, providing an indication of their presence on the external surface. On the other hand, a hematite phase was detected in the solid-state ion exchange of FeCl3 with either HM or NH4M at the loading of 100% Fe. More correlations between Mossbauer data on one hand and XRD and texturing properties on the other hand were evaluated and discussed. (C) 2003 Elsevier Science (USA). All rights reserved.