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Mn-Substituted Goethite and Fe-Substituted Groutite Synthesized At Acid pH1

Published online by Cambridge University Press:  02 April 2024

M. H. Ebinger  and
D. G. Schulze
M. H. Ebinger
Affiliation:
Agronomy Department, Purdue University, West Lafayette, Indiana 47907
D. G. Schulze
Affiliation:
Agronomy Department, Purdue University, West Lafayette, Indiana 47907
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Abstract

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Mn-substituted iron oxides were synthesized by coprecipitating Fe(NO3)3 and Mn(SO4) solutions with NH4OH, adjusting the suspensions to pH 4 or 6, and then keeping the suspensions at 55°C for 62 days. The Mn mole fraction of the final products ranged from 0 to 0.3. X-ray powder diffraction patterns showed that goethite and hematite formed in each Fe-containing system. Groutite formed in systems having initial Mn mole fractions ≥0.35. Only manganite and hausmannite formed in the pure Mn systems. The oxalate-soluble Fe in the samples increased as the Mn mole fraction increased and was slightly larger for the pH 6 series.

For samples that contained the largest Mn mole fraction, the b and c dimensions of the goethite unit cell were shifted toward those of groutite, and the b and c dimensions of the groutite unit cell were shifted toward those of goethite. Assuming the Vegard rule holds for the unit-cell c dimension, the goethite accommodated a maximum Mn mole fraction of 0.34, and the groutite accommodated a maximum Fe mole fraction of 0.31. The unit-cell dimensions of hematite did not vary systematically with the mole fraction of Mn in solution, probably because little Mn substituted into the hematite structure.

Keywords

GoethiteGroutiteIronManganeseSolid solutionSynthesisVegard's lawX-ray powder diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 37 , Issue 2 , April 1989 , pp. 151 - 156
Copyright
Copyright © 1989, The Clay Minerals Society

Footnotes

1

Journal article number 11,250, Purdue Agricultural Experiment Station.

References

ASTM, 1964 Index to the Powder Diffraction File: ASTM Special Technical Publication 48-M1 Philadelphia ASTM 326.Google Scholar
Burns, R. G., 1970 Mineralogical Applications of Crystal Field Theory Cambridge Cambridge University Press 106 – 127.Google Scholar
Chao, T. T. and Theobald, P. K., 1983 The significance of iron and manganese oxides in geochemical exploration Econ. Geol. 71 1560 – 1569.CrossRefGoogle Scholar
Cornell, R. M. and Giovanoli, R., 1987 Effect of manganese on the transformation of ferrihydrite into goethite and jacobsite in alkaline media Clays & Clay Minerals 35 11 – 20.CrossRefGoogle Scholar
Dent-Glasser, L. S. and Ingram, L., 1969 Refinement of the crystal structure of groutite, α-MnOOH Acta Crystallogr. B24 1233 – 1236.Google Scholar
Fernandez, R. N. and Schulze, D. G., 1987 Calculation of soil color from reflectance spectra Soil Sci. Soc. Amer. J. 51 1277 – 1282.CrossRefGoogle Scholar
JCPDS, 1980 Mineral Powder Diffraction Files: Data Book Pennsylvania JCPDS International Center for Diffraction Data, Swarth-more.Google Scholar
Karim, Z., 1984 Influence of transition metals on the formation of iron oxides during the oxidation of Fe(II)Cl2 solution Clays & Clay Minerals 32 334 – 336.CrossRefGoogle Scholar
Klug, H. P. and Alexander, L. E., 1974 X-ray Diffraction Procedures for Polycrystalline and Amorphous Materials New York Wiley.Google Scholar
Lim-Nunez, R., Gilkes, R. J., Schultz, L. G., van Olphen, H. and Mumpton, F. A., 1987 Acid dissolution of synthetic metal containing goethites and hematites Proc. Int. Clay Conf, Denver, 1985 Bloomington, Indiana The Clay Minerals Society 187 – 204.Google Scholar
Lindsay, W. L., 1979 Chemical Equilibria in Soils New York Wiley.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., 1984 The influence of aluminum on iron oxides. VIII. Unit-cell dimensions of Al-substituted goethite and estimation of Al from them Clays & Clay Minerals 32 36 – 44.CrossRefGoogle Scholar
Schulze, D. G., 1986 Correction of mismatches on 20 scales during differential X-ray diffraction Clays & Clay Minerals 34 681 – 685.CrossRefGoogle Scholar
Schwertmann, U., 1964 Differenzierung der Eisenoxide des Bodens durch Extraktion mit einer Ammoniumoxalatlö-sung Pflanzenernaehr. Bodenkd. 105 194 – 202.CrossRefGoogle Scholar
Schwertmann, U., Stucki, J. W., Goodman, B. A. and Schwertmann, U., 1987 Some properties of soil and synthetic iron oxides Iron in Soils and Clay Minerals, Proc. of NATO Adv. Study Inst. Boston D. Reidel 203 – 250.Google Scholar
Schwertmann, U. and Murad, E., 1983 Effect of pH on the formation of goethite and hematite from ferrihydrite Clays & Clay Minerals 31 277 – 284.CrossRefGoogle Scholar
Shannon, R. D. and Prewitt, C. T., 1969 Effective ionic radii in oxides and fluorides Acta Crystallogr. B25 925 – 946.CrossRefGoogle Scholar
Stiers, W. and Schwertmann, U., 1985 Evidence for manganese substitution in synthetic goethite Geochim. Cos-mochim. Acta 49 1909 – 1911.CrossRefGoogle Scholar