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The influence of aluminium on iron oxides: XIII. Properties of goethites synthesised in 0·3 M KOH at 25°C

Published online by Cambridge University Press:  09 July 2018

D. G. Schulze  and
U. Schwertmann
D. G. Schulze
Affiliation:
Agronomy Department, Purdue University, West Lafayette, Indiana 47907, USA
U. Schwertmann
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050 Freising-Weihenstephan, FRG
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Abstract

Aluminium-substituted goethites were synthesised in 0·3 M KOH at either 25° or 70°C. The 25°C goethites had unit-cell a and c dimensions about 0·1–0·2% larger than the 70°C goethites of comparable Al substitution. Unit-cell b dimensions were similar regardless of synthesis temperature. The 25°C goethites contained larger amounts of Al in their structures than the 70°C goethites synthesised at the same initial Al/(Al + Fe) mole ratio in solution. The 25°C goethites had lower dehydroxylation temperatures and smaller differences between the two OH-bending bands than comparable 70°C goethites. These differences between the two sets of goethites are believed to be caused by the presence of more structural defects in the 25°C goethites than in the 70°C goethites. Goethites with the lowest Al substitutions consisted of crystals with several coherently diffracting domains, while at high Al substitutions the crystals were mainly monodomainic. Surface areas of the 25°C goethites varied in a complex manner as a function of thickness along [100], character of the domains, and physical size.

Type
Research Article
Information
Clay Minerals , Volume 22 , Issue 1 , March 1987 , pp. 83 - 92
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1987

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References

Cornell, R.M., Mann, S. & Skarnulis, A.J. (1983) A high-resolution electron microscopy examination of domain boundaries in crystals of synthetic goethite. J. Chem. Soc., Faraday Trans. 1 79, 2679–2684.Google Scholar
Fey, M.V. & Dixon, J.B. (1981) Synthesis and properties of poorly crystalline hydrated aluminous goethites. Clays Clay Miner. 29, 91–100.Google Scholar
Goodman, B.A. & Lewis, D.G. (1981) Mössbauer spectra of aluminous goethites (α-FeOOH). J. Soil Sci. 32, 351–363.CrossRefGoogle Scholar
Klug, H.P. & Alexander, L.E. (1974) X-ray Diffraction Procedures for Polycrystalline and Amorphous Materials. Wiley, New York, 966 pp.Google Scholar
Koutler-Anderson, E. (1953) The sulfosalicylic acid method for iron determinations and its use in certain soil analyses. Ann. Roy. Agric. Coll. Sweden 20, 297–308.Google Scholar
Lewis, D.G. & Schwertmann, U. (1979a) The influence of Al on iron oxides: Part III. Preparation of Al goethites in M KOH. Clay Miner. 14, 115–126.Google Scholar
Lewis, D.G. & Schwertmann, U. (1979b) The influence of aluminum on the formation of iron oxides: IV. The influence of [Al], [OH], and temperature. Clays Clay Miner. 27, 195–200.Google Scholar
Schulze, D.G. (1984) The influence of aluminum on iron oxides: VII. Unit cell dimensions of Al-substituted goethites and estimation of Al from them. Clays Clay Miner. 32, 3644.Google Scholar
Schulze, D.G. (1981) Identification of soil iron oxide minerals by differential X-ray diffraction. Soil Sci. Soc. Am. J. 45, 437–440.CrossRefGoogle Scholar
Schulze, D.G. & Schwertmann, U. (1984) The influence of aluminium on iron oxides: X. Properties of Al- substituted goethites. Clay Miner. 19, 521–539.CrossRefGoogle Scholar
Schwertmann, U. (1964). Differenzierung der Eisenoxide des Bodens durch Extraktion mit Ammoniumoxalat-Lösung. Z. Pflanzenern. Düng. Bodenkunde 105, 194–202.Google Scholar
Schwertmann, U., Cambier, P. & Murad, E. (1985) Properties of goethites of varying crystallinity. Clays Clay Miner. 33, 369–378.CrossRefGoogle Scholar
Schwertmann, U. & Kämpf, N. (1985) Properties of goethite and hematite in kaolinitic soils of southern and central Brazil. Soil Sci. 139, 344–350.Google Scholar
Schwertmann, U. & Taylor, R.M. (1986) Iron oxides: in Minerals in Soil Environments, 2nd ed. (Dixon, J. B. & Weed, S. B., editors). Soil Sci. Soc. Am., Madison, Wisconsin (in press).Google Scholar