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The Influence of Aluminum on Iron Oxides. VIII. Unit-Cell Dimensions of Al-Substituted Goethites and Estimation of Al from them

Published online by Cambridge University Press:  02 April 2024

D. G. Schulze
D. G. Schulze*
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050 Freising-Weihenstephan, Federal Republic of Germany
*
1Present address: Department of Agronomy, Purdue University, West Lafayette, Indiana, 47907.
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Abstract

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The unit-cell dimensions of synthetic, Al-substituted goethites showed that the c dimension is a linear function of Al substitution in the range 0–33 mole % Al, but that the a dimension is variable over this same range. The b dimension is also linearly related to Al substitution but is slightly more variable than the c dimension for Al substitutions of 20–33 mole %. The variability of the a dimension is postulated to be the result of structural defects. An improved procedure for estimating Al substitution from x-ray powder diffraction positions requires (1) calculation of the c dimension from the positions of the 110 and 111 diffraction lines using the formula: c = (1/d(111)2 − 1/d(110)2)−1/2, and (2) estimation of Al substitution from the relationship: mole % Al = 1730 − 572.0c. The 95% confidence interval of the estimate is ±2.6 mole % Al when using this procedure, in contrast to ±4.0 mole % Al when the position of the 111 reflection alone is used.

Резюме

Резюме

Размеры элементарной ячейки синтетических, Al-замещенных гетитов указывали на то, что размерность c является линейной фуркцией замещения Al в диапазоне от 0 до 33 молярных % Al, тогда как размерность a является переменной на том же самом диапазоне. Размерность b также являлась линейно зависимой от замещения Al, но проявляла слегка большую изменчи-вость чем с для замещения Al в диапазоне 20 до 33 молярных %. Предлагается, что изменчивость размерности является результатом структурных дефектов. Улучшенная процедура для оценки замещения Al на основе положений линий рентгеновской порошковой дифракции требует: (1) вычисления размерности c на основе положений 100 и 111 дифракционных линий используя формулу: c = (1/d(111)2 − 1/d(110)2)−1/2 и (2) оценки замещения Al из соотношения: молярные % Al = 1730 − 572,0 c. 95% уровень статистической достоверности этой оценки равен ±2,6 молярных % Al при использовании этой процедуры, в противоположность 4,0 молярных % Al когда только используется положение отражения 111. [E.G.]

Resümee

Resümee

Die Größen der Einheitszellen von synthetischen, Al-substituierten Goethiten zeigten, daß die c-Dimension eine lineare Funktion der Al-Substitution im Bereich von 0–33 Mol.-% Al ist, daß aber die a-Dimension in diesem Bereich variiert. Die b-Dimension zeigt ebenfalls eine lineare Abhängigkeit von der Al-Substitution, variiert aber etwas mehr als c bei Al-Substitution zwischen 20–33 Mol.-%. Es wird vorgeschlagen, daß die Variation der a-Dimension das Ergebnis von Gitterfehlern ist. Eine verbesserte Vorgangsweise zur Abschätzung der Al-Substitution aus der Lage der XRD-Linien erfordert (1) die Berechnung der c-Dimension aus der Lage der 110 und 111 Linien, wozu die Formel c = (1/d(111)2 − 1/d(110)2)−1/2 zu verwenden ist und (2) die Abschätzung der Al-Substitution aus der Beziehung: Mol.-% Al = 1730 − 572,0 c. Das Konfidenzintervall der Abschätzung beträgt ±2,6 Mol.-% Al, wenn man diese Vorgangsweise anwendet, im Gegensatz zu ±4,0 Mol.-% Al, wenn die Lage des 111 Reflexes allein berücksichtigt wird. [U.W.]

Résumé

Résumé

Les dimensions de la maille-mère de goethites synthétiques substituées par Al ont montré que la dimension c est une fonction linéaire de la substitution par Al sur l’étendue 0–33 mole % d'Al, mais que la dimension a est variable sur cette même étendue. La dimension b était aussi apparentée linéairement à la substitution par Al, mais s'est montrée quelque peu plus variable que c, pour la substitution par Al de 20–33 mole %. On a proposé que la variabilité de la dimension a est un résultat de défauts structuraux. Un procédé amelioré pour estimer la substitution par Al à partir de positions de droite XRD exige (I) le calcul de la dimension c à partir des positions des droites de diffraction 110 et 111 en employant la formule: c = (1/d(111)2 − 1/d(110)2−1/2, et (2) l'estimation de la substitution par Al à partir de la relation: mole % d'Al = 1730 − 572,0 c. L'interval de confiance 95% de cette estimation est ±2,6 mole % d'Al en employant ce procédé, en contraste avec ±4,0 mole % d'Al lorsque seule la position de la réflection 111 est utilisée. [D.J.]

Keywords

AluminumGoethiteIronUnit-cell dimensionsX-ray powder diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 32 , Issue 1 , February 1984 , pp. 36 - 44
Copyright
Copyright © 1984, The Clay Minerals Society

References

Literature Cited

Bigham, J. M., Golden, D. C., Bowen, L. H., Buol, S. W. and Weed, S. B., 1978 Iron oxide mineralogy of well-drained Ultisols and Oxisols: I. Characterization of iron oxides in soil clays by Mössbauer spectroscopy, X-ray diffractometry, and selected chemical techniques. Soil Sci. Soc. Amer. J 42 816–825.CrossRefGoogle Scholar
Brindley, G. W., Brindley, G. W. and Brown, G., 1980 Order-disorder in clay mineral structures Crystal Structures of Clay Minerals and Their X-ray Identification London Mineralogical Society 125–195.CrossRefGoogle Scholar
Brown, G., Brindley, G. W. and Brown, G., 1980 Associated minerals Crystal Structures of Clay Minerals and Their X-ray Identification London Mineralogical Society 361–410.CrossRefGoogle Scholar
Davey, B. G., Russell, J. D. and Wilson, M. J., 1975 Iron oxide and clay minerals and their relation to colours of red and yellow Podzolic soils near Sydney, Australia Geoder-ma 14 125–138.CrossRefGoogle Scholar
Ewing, F. J., 1935 The crystal structure of diaspore J. Chem. Phys 3 203–207.CrossRefGoogle Scholar
Fey, M. V. and Dixon, J. B., 1981 Synthesis and properties of poorly crystalline hydrated aluminous goethites. Clays & Clay Minerals 29 91–100.CrossRefGoogle Scholar
Fitzpatrick, R. W., 1978 Occurrence and properties of iron and titanium oxides in soils along the eastern seaboard of South Africa .Google Scholar
Fitzpatrick, R. W. and Schwertmann, U., 1981 Al-substituted goethite—an indicator of pedogenic and other weathering environments in South Africa Geoderma 27 335–347.CrossRefGoogle Scholar
Golden, D. C., 1978 Physical and chemical properties of aluminum-substituted goethite .Google Scholar
Goodman, B. A. and Lewis, D. G., 1981 Mössbauer spectra of aluminous goethites (α-FeOOH) J. Soil Sci 32 351–363.CrossRefGoogle Scholar
Hoppe, W., 1941 Über die Kristallstruktur von α-AlOOH (Diaspor) und α-FeOOH (Nadeleisenerz) Kristallogr 103 73–89.Google Scholar
Janik, J. L. and Raupach, M. (1977) An iterative least-squares program to separate infrared absorption spectra into their component bands. CSIRO, Div. of Soils Tech. Paper 35, 37 pp.Google Scholar
Janot, C., Gibert, H., de Gramont, X. and Biais, R., 1971 Étude des substitutions Al-Fe dans des roches latéritiques Bull. Soc. Fr. Minéral. Cristallogr 94 367–380.Google Scholar
JCPDS, 1974 Selected powder diffraction data for minerals—Data Book.Google Scholar
Jónás, K. and Solymár, K., 1970 Preparation, X-ray, de-rivatographic and infrared study of aluminum-substituted goethites Acta Chim. Acad. Sci. Hung 66 383–394.Google Scholar
Kämpf, N., 1981 Die Eisenoxidmineralogie einer Klimasequenz von Böden aus Eruptiva in Rio Grande do Sul, Brasilien .Google Scholar
Kämpf, N. and Schwertmann, U., 1982 The 5-M-NaOH concentration treatment for iron oxides in soils Clays & Clay Minerals 30 401–408.CrossRefGoogle Scholar
Klug, H. P. and Alexander, L. E., 1974 X-ray Diffraction Procedures for Polycrystalline and Amorphous Materials New York Wiley.Google Scholar
Lewis, D. G. and Schwertmann, U., 1979 The influence of Al on iron oxides. Part III. Preparation of Al goethites in M KOH Clay Min 14 115–126.CrossRefGoogle Scholar
Lewis, D. G. and Schwertmann, U., 1979 The influence of aluminum on the formation of iron oxides. IV. The influence of [Al], [OH], and temperature Clays & Clay Minerals 27 195–200.CrossRefGoogle Scholar
Mendelovici, E., Yariv, S.h. and Villalba, R., 1979 Aluminum-bearing goethite in Venezuelan latentes. Clays & Clay Minerals 27 368–372.CrossRefGoogle Scholar
Mehra, O. P., Jackson, M. L. and Swineford, A., 1960 Iron oxide removal from soils and clays by a dithionite-citrate-bicarbonate system buffered with sodium bicarbonate Clays and Clay Minerals, Proc. 7th Natl. Conf., Washington, D.C., 1958 New York Pergamon Press 317–327.Google Scholar
Nahon, D., Janot, C., Karpoff, A. M., Paquet, H. and Tardy, Y., 1977 Mineralogy, petrography and structures of iron crusts (ferricretes) developed on sandstones in the western part of Senegal Geoderma 19 263–277.CrossRefGoogle Scholar
Norrish, K. and Taylor, R. M., 1961 The isomorphous replacement of iron by aluminium in soil goethites J. Soil Sci 12 294–306.CrossRefGoogle Scholar
Schellmann, W., 1964 Zur Rolle des Aluminiums in Nadeleisenerz-Ooiden N. Jb. Miner. Mh 2 49–56.Google Scholar
Scheiderhöhn, P., 1964 Über das Vorkommen des Aluminiums in einer ooidische Eisenerze enthaltenden marinen Schichtfolge Beitr. Miner. Petrogr 10 141–151.Google Scholar
Schwertmann, U., 1959 Über die Synthese definierter Eisenoxyde unter verschiedenen Bedingungen Z. Anorg. Allg. Chemie 298 337–348.CrossRefGoogle Scholar
Schwertmann, U., Taylor, R. M., Dixon, J. B. and Weed, S. B., 1977 Iron oxides Minerals in Soil Environments 145–180.Google Scholar
Schulze, D. G., 1981 Identification of soil iron oxide minerals by differential X-ray diffraction Soil Sci. Soc. Amer. J 45 437–440.CrossRefGoogle Scholar
Schulze, D. G., 1982 The identification of iron oxides by differential X-ray diffraction and the influence of aluminum substitution on the structure of goethite .Google Scholar
Schulze, D. G. and Dixon, J. B., 1979 High gradient magnetic separation of iron oxide and other magnetic minerals from soil clays. Soil Sci. Soc. Amer. J 43 793–799.CrossRefGoogle Scholar
Shannon, R. D. and Prewitt, C. T., 1969 Effective ionic radii in oxides and fluorides Acta Cryst B25 925–946.CrossRefGoogle Scholar
Taylor, R. M. and Schwertmann, U., 1978 The influence of aluminum on iron oxides. Part I. The influence of Al on Fe oxide formation from the Fe(II) system Clays & Clay Minerals 26 373–383.CrossRefGoogle Scholar
Thiel, R., 1963 Zum System α-FeOOH-α-AlOOH Z. Anorg. Allg. Chem 326 70–78.CrossRefGoogle Scholar
Torrent, J., Schwertmann, U. and Schulze, D. G., 1980 Iron oxide mineralogy of some soils of two river terrace sequences in Spain Geoderma 23 191–208.CrossRefGoogle Scholar