MÖSSBAUER SPECTRA OF ALUMINOUS GOETHITES (α‐FeOOH)

Abstract
Summary: Synthethic goethite specimens have been prepared by a variety of experimental methods, and it has been possible to incorporate large quantities of Al ( 30 mol %) into the structure. A range of particle sizes also obtained and these were dependent upon both experimental conditions and the extent of aluminium substitution. Mössbauer spectra have been recorded for a large number of samples and show that high levels of A1‐substitution combined with small particle sizes have a dramatic effect on the magnetic properties of the mineral. The application of Mössbauer spectroscopy to the identification of secondary iron oxide phases in soils is thus complicated by aluminium substitution and some of the difficulties are discussed.