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The influence of aluminium on iron oxides: X. properties of Al-substituted goethites

Published online by Cambridge University Press:  09 July 2018

D. G. Schulze  and
U. Schwertmann
D. G. Schulze
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050, Freising-WeihenstephanFRG
U. Schwertmann
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050, Freising-WeihenstephanFRG
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Abstract

Fifty-seven goethites, synthesized by a variety of procedures and with Al substitutions of 0–33 mole%, were characterized by XRD, IR, DTA, TEM and chemical techniques. Most of the properties measured showed significant intercorrelations. Mole% Al substitution (measured chemically) did not explain all the relationships among variables, but the inclusion of Δa, defined as the observed a dimension minus the a dimension predicted by the Vegard rule, explained much of the variation not explained by Al substitution. OH stretching frequency, in particular, was better correlated with Δa than the Al substitution or other properties. The properties of the goethites could best be explained by a combination of Al substitution and structural defects, with Δa being a measure of the defects. In general, the effect of structural defects was opposite to that of Al substitution. Increase in Al substitution led to a decrease in all three unit-cell dimensions and OH stretching frequency and to an increase in the distance between the two OH bending vibrations (δOH-γOH) and the temperature of dehydroxylation. Increase in structural defects, on the other hand, caused the a dimension, Δa, and OH stretching frequency to increase and δOH-γOH and the average temperature of dehydroxylation to decrease. Crystal size tended to decrease with increases in both Al substitution and structural defects. Surface area was significantly correlated with the reciprocal of the mean crystal thickness in the a direction. Comparison of XRD and TEM data showed that many samples consisted of crystals with several coherently scattering domains. The nature of the defects, i.e. whether they occur primarily in the interdomain areas or whether they are also distributed throughout the coherently diffracting domains, could not be determined.

Type
Research Article
Information
Clay Minerals , Volume 19 , Issue 4 , September 1984 , pp. 521 - 539
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1984

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References

Brown, G. (1980) Associated minerals. Pp. 361–410 in: Crystal Structures of Clay Minerals and their X-ray Identification (Brindley, G. W. & Brown, G., editors). Mineralogical Society, London.CrossRefGoogle Scholar
Busing, W. R. & Levy, H. A. (1958) A single crystal neutron diffraction study of diaspore, AIO(OH). Acta Cryst. 11, 798–803.Google Scholar
Carter, D. L., Heilman, M. D. & Gonzalez, C. L. (1965) Ethylene glycol monoethyl ether for determining surface area of silicate minerals. Soil Sci. 100, 798–803 Google Scholar
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
Egashira, K. & Aomine, S. (1974) Effects of drying and heating on the surface area of allophane and imogolite. Clay Sci. 4, 231–242.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
Forsyth, J. B., Hedley, I. G. & Johnson, C. E. (1968) The magnetic structure and hyperfine field of goethite (α-FeOOH). J. Phys. C (Proc. Phys. Soc.) Ser. 2, 1, 179–188.CrossRefGoogle Scholar
Golden, D. C. (1978) Physical and chemical properties of aluminum-substituted goethite. PhD Thesis, North Carolina State Univ., Raleigh, North Carolina. 174 pp.Google Scholar
Golden, D. C., Bowen, L. H., Weed, S. B. & Bigham, J. M. (1979) Mössbauer studies of synthetic and soiloccurring aluminum-substituted goethites. Soil Sci. Soc. Am. J. 43, 802–808.Google Scholar
Joint Committee On Powder Diffraction Standards (Jcpds) (1974) Selected Powder Diffraction Data for Minerals. Swarthmore, Pennsylvania.Google Scholar
Jónás, K. & Solymár, K. (1970) Preparation, X-ray, derivatographic and infrared study of aluminumsubstituted goethites. Acta Chim. Acad. Sci. Hung. 66, 383–394.Google Scholar
Klug, H. P. & Alexander, L. E. (1974) X-ray Diffraction Procedures for Polycrystalline and Amorphous Materials, 2nd Ed. John Wiley & Sons, New York. 966 pp.Google Scholar
Mackenzle, R. C. & Berggren, G. (1970) Oxides and hydroxides of higher valency elements. Pp. 271–302 in. Differential Thermal Analysis 1, (Mackenzie, R. C., editor). Academic Press, New York.Google Scholar
Mann, S., Cornell, R. M. & Schwertmann, U. (1985) High-resolution transmission electron microscopic (HRTEM) study of aluminous goethites. Clay Miner. 20 (in press).Google Scholar
Mendelovici, E., Yariv, Sh. & Villalba, R. (1979) Aluminum-bearing goethite in Venezuelan laterites. Clays Clay Miner. 27, 368–372.Google Scholar
Murad, E. & Schwertmann, U. (1983) The influence of aluminium substitution and crystallinity on the Mössbauer spectra of goethite. Clay Miner. 18, 301–312.Google Scholar
Sampson, C. F. (1969) The lattice parameters of natural single crystal and synthetically produced goethite (α-FeOOH). Acta Cryst. B25, 1683–1685.Google Scholar
Schulze, D. G. (1984) The influence of aluminum on iron oxides VIII. Unit-cell dimensions of Al-substituted goethites and estimation of Al from them. Clays Clay Miner. 32, 36–44.Google Scholar
Scnulze, D. G. (1982) The identification of iron oxide minerals by differential X-ray diffraction and the influence of aluminum substitution on the structure of goethite. PhD Thesis, Technische Universität Munchen, Freising-Weihenstephan, German Federal Republic. University Microfilms International, Ann Arbor, Michigan. 167 pp.Google Scholar
Schwarzmann, E. & Sparr, H. (1969) Die Wasserstoffbrückenbindung in Hydroxiden mit Diasporstruktur. Z. Naturforsch. 24b, 8–11.CrossRefGoogle Scholar
Schwegtmann, U. (1984a) The double dehydroxylation peak of goethite. Thermochim. Acta (in press).Google Scholar
Schwertmann, U. (1984b) The influence of aluminium on iron oxides. IX. Dissolution of Al-goethites in 6 M HCl. Clay Miner. 19, 9–19.Google Scholar
Smith, K. L. & Eggleton, R. A. (1983) Microstructures of botryoidal goethites. Clays Clay Miner. 31, 392–396.Google Scholar
Thiel, R. (1963) Zum System α-FeOOH-α-AIOOH. Z. Anorg. Allg. Chem. 326, 70–78.CrossRefGoogle Scholar
Turner, S. & Buseck, P. R. (1983) Defects in nsutite (γ-MnO2) and dry-cell battery efficiency. Nature 304, 143–146.Google Scholar
Van Osterhout, G. W. (1964) The structure of goethite. Pp. 529–532 in: Proc. 5th Int. Conf. on Magnetism. Nottingham.Google Scholar