Mössbauer studies of ferrous-a zeolite. Part 1.—Adsorption/desorption of water

Abstract

Ferrous ions have been ion exchanged into A zeolite. The ferrous ions in the dehydrated form of the zeolite give an isomer shift of 1.08 mm s^–1 and a temperature independent quadrupole splitting of 0.46 mm s^–1. The ferrous ions are shown to be located in the sodalite window site with 3-fold coordination to lattice oxygens.

In the partially hydrated zeolite two species of iron are seen in the Mössbauer spectra. Temperature studies show these two sites to be related by an equilibrium process, which is interpreted as the dissociation of a water molecule attached to a ferrous ion to give a hydroxyl group.