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Thermodynamic Properties of Feroxyhyte (δ′-FeOOH)

Published online by Cambridge University Press:  01 January 2024

Juraj Majzlan ,
Christian Bender Koch  and
Alexandra Navrotsky
Juraj Majzlan*
Affiliation:
Institute of Mineralogy and Geochemistry, Albertstraße 23b, Albert-Ludwig University, Freiburg, D-79104 Germany
Christian Bender Koch
Affiliation:
Department of Natural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
Alexandra Navrotsky
Affiliation:
Thermochemistry Facility, One Shields Avenue, University of California at Davis, 95616 Davis, CA, USA
*
* E-mail address of corresponding author: Juraj.Majzlan@minpet.uni-freiburg.de
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Abstract

Feroxyhyte (δ′-FeOOH) is a relatively uncommon Fe oxide mineral and one of the few phases in the system Fe2O3-H2O for which thermodynamic properties are not known. In natural occurrences, it is always fine-grained, although samples with larger particle sizes and better crystallinity (labeled as δ-FeOOH) can be prepared in the laboratory. This contribution presents a thermochemical study on a series of feroxyhyte samples. One is fine-grained and poorly crystalline, similar to natural materials, while the other three are of better crystallinity. The enthalpy of formation of feroxyhyte at 298.15 K is −547.4±1.3kJ mol−1 for the poorly crystalline sample (surface area 88 m2/g), and −550.6±1.4, −550.9±1.3, and −552.6±1.2 kJ mol−1 for the samples with better crystallinity. The entropy of feroxyhyte can be estimated only crudely, because it is influenced to a great extent by its magnetic properties, particle size, and structural disorder. The S298o$S_{298}^{\rm{o}}$ of feroxyhyte is estimated here to be 65±5 J K−1 mol−1. The Gibbs free energy of the reaction feroxyhyte → hematite + liquid water is −7.4 to −12.6 kJ mol−1 at 298.15 K. The Gibbs free energy of formation (ΔGfo${\rm{\Delta }}G_{\rm{f}}^{\rm{o}}$) of the fine-grained, poorly crystalline feroxyhyte is −478.1±2.0 kJ mol−1 at 298.15 K. Since this sample is closest in its physical properties to natural feroxyhyte, this ΔGfo${\rm{\Delta }}G_{\rm{f}}^{\rm{o}}$ value should be used in thermodynamic modeling related to processes involving naturally occurring feroxyhyte. In terms of Gibbs free energy and enthalpy, feroxyhyte is very similar to lepidocrocite and maghemite, and, like these two phases, has no thermodynamic stability field in the system Fe2O3-H2O, except possibly at the nanoscale.

Keywords

Enthalpy of FormationFeroxyhyteThermodynamic Stability

Information

Type
Article
Information
Clays and Clay Minerals , Volume 56 , Issue 5 , October 2008 , pp. 526 - 530
Copyright
Copyright © The Clay Minerals Society 2009

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References

Brunauer, S. Emmett, P.H. and Teller, E., 1938 Adsorption of gases in multimolecular layers Journal of the American Chemical Society 60 308–319 10.1021/ja01269a023.CrossRefGoogle Scholar
Burns, R.G., 1980 Does feroxyhyte occur on the surface of Mars? Nature 285 647 10.1038/285647a0.CrossRefGoogle Scholar
Carlson, L. and Schwertmann, U., 1980 Natural occurrence of feroxyhyte (δ′-FeOOH) Clays and Clay Minerals 28 272–280 10.1346/CCMN.1980.0280405.CrossRefGoogle Scholar
Chukrov, F.V. Zvyagin, B.B. Gorshkov, A.I. Ermilova, L.P. Korovushkin, V.V. Rudnitskaya, E.S. and Yakubovskaya, E.S., 1976 Feroxyhyte, a new modification of FeOOH Izvestiya Akademii Nauk SSSR, Seriya Geologicheskaya 5 5–24.Google Scholar
Dasgupta, D.R., 1961 Topotactic transformations in iron oxides and hydroxides Indian Journal of Physics 35 7.Google Scholar
Drits, V.A. Sakharov, B.A. and Manceau, A., 1993 Structure of feroxyhyte as determined by simulation of X-ray diffraction curves Clay Minerals 28 209–222 10.1180/claymin.1993.028.2.03.CrossRefGoogle Scholar
Glemser, O. and Gwinner, E., 1939 Über eine neue, ferromagnetische Modifikation des Eisen(III) oxyds Zeitschrift für anorganische Chemie 240 161–166 10.1002/zaac.19392400209.CrossRefGoogle Scholar
Koch, C. Oxborrow, C.A. Mørup, S. Madsen, M.B. Quinn, A.J. and Coey, J.M.D., 1995 Magnetic properties of feroxyhyte (δ-FeOOH) Physics and Chemistry of Minerals 22 333–341 10.1007/BF00202774.CrossRefGoogle Scholar
Majzlan, J. Grevel, K.-D. and Navrotsky, A., 2003 Thermodynamics of iron oxides: Part II. Enthalpies of formation and relative stability of goethite (α-FeOOH), lepidocrocite (γ-FeOOH), and maghemite (γ-Fe2O3) American Mineralogist 88 855–859 10.2138/am-2003-5-614.CrossRefGoogle Scholar
Majzlan, J. Lang, B.E. Stevens, R. Navrotsky, A. Woodfield, B.F. and Boerio-Goates, J., 2003 Thermodynamics of iron oxides: Part I. Standard entropy and heat capacity of goethite (α-FeOOH), lepidocrocite (γ-FeOOH), and maghemite (γ-Fe2O3) American Mineralogist 88 846–854 10.2138/am-2003-5-613.CrossRefGoogle Scholar
Manceau, A. and Drits, V.A., 1993 Local structure of ferrihydrite and feroxyhite by EXAFS spectroscopy Clay Minerals 28 165–184 10.1180/claymin.1993.028.2.01.CrossRefGoogle Scholar
Mazeina, L. and Navrotsky, A., 2007 Enthalpy of water adsorption and surface enthalpy of goethite (α-FeOOH) and hematite (α-Fe2O3) Chemistry of Materials 19 825–833 10.1021/cm0623817.CrossRefGoogle Scholar
Mazeina, L. Deore, S. and Navrotsky, A., 2006 Energetics of bulk and nano-akaganeite, β-FeOOH: Enthalpy of formation, surface enthalpy, and enthalpy of water adsorption Chemistry of Materials 18 1830–1838 10.1021/cm052543j.CrossRefGoogle Scholar
McHale, J.M. Auroux, A. Perrotta, A.J. and Navrotsky, A., 1997 Surface energies and thermodynamic phase stability in nanocrystalline aluminas Science 277 788–791 10.1126/science.277.5327.788.CrossRefGoogle Scholar
Parise, J.B. Marshall, W.G. Smith, R.I. Lutz, H.D. and Möller, H., 2000 The nuclear and magnetic structure of ‘white rust’ — Fe(OH0.86D0.14)2 American Mineralogist 85 189–193 10.2138/am-2000-0118.CrossRefGoogle Scholar
Patrat, G. de Bergevin, F. Pernet, M. and Joubert, J.C., 1983 Structure locale de δ-FeOOH Acta Crystallographica B39 165–170 10.1107/S0108768183002232.CrossRefGoogle Scholar
Pitcher, M.W. Ushakov, S.V. Navrotsky, A. Woodfield, B.F. Li, G. Boerio-Goates, J. and Tissue, B.M., 2005 Energy crossovers in nanocrystalline zirconia Journal of the American Ceramic Society 88 160–167 10.1111/j.1551-2916.2004.00031.x.CrossRefGoogle Scholar
Robie, R.A. and Hemingway, B.S. (1995) Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (105 Pascals) and at higher temperatures. U.S. Geological Survey Bulletin, 2131, 461 pp.Google Scholar
Schwertmann, U. and Cornell, R.M., 2000 Iron Oxides in the Laboratory Weinheim, Germany Wiley-VCH 10.1002/9783527613229.CrossRefGoogle Scholar
van Parker, B. (1965) Thermal properties of uni-univalent electrolytes. National Standard Reference Data Series, National Bureau of Standards, 2, 66 pp.Google Scholar