A new route to γ-Fe2O3via an intermediate oxyhydroxide. The reaction of α-NaFeO2 with benzoic acid

Abstract

Proton exchange reactions have been performed on α-NaFeO ₂ at 150 °C in molten benzoic acid; a ferrimagnetic material showing the spinel structure was produced. Infrared spectroscopy was used to investigate the oxyhydroxide character of this product which, after thermal treatment at 300 °C yields the well known maghemite γ-Fe ₂ O ₃ , although some hydroxyl groups still seem to be present. Besides IR, X-ray diffraction, chemical and thermal analysis, Mössbauer spectroscopy and magnetization measurements are presented and discussed.