Abstract
The iron (Fe) L2,3-edge X-ray absorption near-edge structure (XANES) spectrum is sensitive to the local coordination environment around the Fe metal center, making it a useful probe for understanding Fe mineral speciation. The two dominant spectral peaks in the Fe L3-edge are parameterized according to the difference in the energy position (ΔeV), and the quotient (intensity ratio) of the two peaks’ maxima. Variations in the ΔeV value are strongly linked to factors that impact on the strength of the ligand field (e.g., Fe valence state, coordination number, and the nature of ligand bonding). The intensity ratio is affected by the strength of the ligand field and by the composition of the resultant molecular orbitals. The Fe valence state also strongly affects the intensity ratio, and an intensity ratio equal to one can be used to distinguish between Fe2+ and Fe3+ minerals. The effects of polyhedral distortion on the magnitudes of ΔeV and intensity ratio values were tested by considering the Fe oxide and -oxy- hydroxide mineral system, in which ligand effects are limited to the differences between the oxygen and hydroxyl ligands. In this system, the distribution of Fe oxide and -oxy-hydroxide minerals on a ΔeV vs. intensity ratio two-parameter plot could be explained by considering the Fe valence state, the ligand chemistry and the site symmetry of the Fe polyhedra. Furthermore, the ΔeV and intensity ratio values were found to be anti-correlated with respect to the various distortion measures considered in this study (e.g., polyhedral volume distortion percentage). This two-parameter plot is thus presented as a standard-less phase-specific identification tool for use in Fe speciation studies, applicable to both natural systems (e.g., aerosols, aquatic colloids) as well as to engineered systems (e.g., nanoparticle synthesis). A major advantage of this technique is that it is applicable to both crystalline and poorly crystalline phases, thus enhancing our ability to study amorphous and nano-crystalline phases that are typically difficult to characterize using X-ray diffraction techniques.
Acknowledgments
This research is supported by grants from NRF, South Africa (Blue Skies Program), Stellenbosch University VR(R) fund, NSF (chemical sciences), U.S.- DOE (B.E.S. and S.B.R.), and Princeton University. The authors thank the support staff at the Advanced Light Source for helping with data collection and sample preparation and L. Barbour for his help with the crystallographic program XSeed.
References cited
Appelo, C.A.J., and Postma, D. (2004) Geochemistry, Groundwater and Pollution, p. 649 pp. CRC Press.10.1201/9781439833544Search in Google Scholar
Atwood, J.L., and Barbour, L.J. (2003) Molecular graphics: from science to art. Crystal Growth & Design, 3, 3.10.1021/cg020063oSearch in Google Scholar
Augustsson, A., Zhuang, G.V., Butorin, S.M., Osorio-Guillen, J.M., Dong, C.L., Ahuja, R., Chang, C.L., Ross, P.N., Nordgren, J., and Guo J.-H. (2005) Electronic structure of phospho-olivines LixFePO4 (x = 0, 1) from soft-X-ray-absorption and -emission spectroscopies. Journal of Chemical Physics, 123, 184717.10.1063/1.2107387Search in Google Scholar PubMed
Balić-Žunić, T. (2007) Use of three-dimensional parameters in the analysis of crystal structures under compression. In A. Grzechnik, Ed., Pressure-induced Phase Transitions, p. 157–184. Transworld Research Network, Trivandrum.Search in Google Scholar
Balić-Žunić, T., and Vickovic, I. (1996) IVTON—program for the calculation of geometrical aspects of crystal structures and some crystal chemical applications. Journal of Applied Crystallography, 29, 305–306.10.1107/S0021889895015081Search in Google Scholar
Benzerara, K., Menguy, N., Banerjee, N.R., Tyliszczak, T., Brown, G.E. Jr., and Guyot, F. (2007) Alteration of submarine basaltic glass from the Ontong Java Plateau: A STXM and TEM study. Earth and Planetary Science Letters, 260, 187–200.10.1016/j.epsl.2007.05.029Search in Google Scholar
Blake, R.L., Hessevick, R.E., Zoltai, T., and Finger, L.W. (1966) Refinement of the hematite structure. American Mineralogist, 51, 123–129.Search in Google Scholar
Bluhm, H., Andersson, K., Araki, T., Benzerara, K., Brown, G.E., Dynes, J.J., Ghosal, S., Gilles, M.K., Hansen, H.-Ch., Hemminger, J.C., and others (2006) Soft X-ray microscopy and spectroscopy at the molecular environmental science beamline at the Advanced Light Source. Journal of Electron Spectroscopy and Related Phenomena, 150, 86–104.10.1016/j.elspec.2005.07.005Search in Google Scholar
Bourdelle, F., Benzerara, K., Beyssac, O., Cosmidis, J., Neuville, D.R., Brown, G.E., and Paineau, E. (2013) Quantification of the ferric/ferrous iron ratio in silicates by scanning transmission X-ray microscopy at the Fe L2,3 edges. Contributions to Mineralogy and Petrology, 166, 423–434.10.1007/s00410-013-0883-4Search in Google Scholar
Burns, R.G. (1970) Mineralogical applications of crystal field theory. In W.B. Harland, S.O. Agrell, D. Davies, and H.F. Hughes, Eds. Cambridge University Press.Search in Google Scholar
Calvert, C.C., Brown, A., and Brydson, R. (2005) Determination of the local chemistry of iron in inorganic and organic materials. Journal of Electron Spectroscopy and Related Phenomena, 143, 173–187.10.1016/j.elspec.2004.03.012Search in Google Scholar
Cavé, L., Al, T., Loomer, D., Cogswell, S., and Weaver, L. (2006) A STEM/EELS method for mapping iron valence ratios in oxide minerals. Micron, 37, 301–309.10.1016/j.micron.2005.10.006Search in Google Scholar PubMed
Chan, C.S., De Stasio, G., Welch, S.A., Girasole, M., Frazer, B.H., Nesterova, M.V., Fakra, S., and Banfield, J.F. (2004) Microbial polysaccharides template assembly of nanocrystal fibers. Science, 303, 1656–1658.10.1126/science.1092098Search in Google Scholar PubMed
Chan, C.S., Fakra, S.C., Edwards, D.C., Emerson, D., and Banfield, J.F. (2009) Iron oxyhydroxide mineralization on microbial extracellular polysaccharides. Geochimica et Cosmochimica Acta, 73, 3807–3818.10.1016/j.gca.2009.02.036Search in Google Scholar
Chen, C., and Sparks, D.L. (2015) Multi-elemental scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectroscopy assessment of organo-mineral associations in soils from reduced environments. Environmental Chemistry, 12, 64–73.10.1071/EN14042Search in Google Scholar
Chen, K.-F., Lo, S.-C., Chang, L., Egerton, R., Kai, J.-J., Lin, J.-J., and Chen, F.-R. (2007) Valence state map of iron oxide thin film obtained from electron spectroscopy imaging series. Micron, 38, 354–361.10.1016/j.micron.2006.06.004Search in Google Scholar
Cornell, R.M., and Schwertmann, U. (2003) The Iron Oxides: Structure, properties, reactions, occurrences and uses. Weinheim, New York.10.1002/3527602097Search in Google Scholar
Cramer, S.P., DeGroot, F.M.F., Ma, Y., Chen, C.T., Sette, F., Kipke, C.A., Eichhorn, D.M., Chan, M.K., and Armstrong, W.H. (1991) Ligand field strengths and oxidation states from manganese L-edge spectroscopy. Journal of the American Chemical Society, 113, 7937–7940.10.1021/ja00021a018Search in Google Scholar
Cramer, S.P., Chen, J., George, S.J., van Elp, J., Moore, J., Tensch, O., Colaresi, J., Yocum, M., Mullins, O.C., and Chen, C.T. (1992) Soft-ray spectroscopy of metalloproteins using fluorescence detection. Nuclear Instruments and Methods in Physics Research Section A, 319, 285–289.10.1016/0168-9002(92)90567-NSearch in Google Scholar
Cressey, G., Henderson, C.M.B., and van der Laan, G. (1993) Use of L-edge X-ray absorption spectroscopy to characterize multiple valence states of 3d transition metals; a new probe for mineralogical and geochemical research. Physics and Chemistry of Minerals, 20, 111–119.10.1007/BF00207204Search in Google Scholar
Crocombette, J.P., Pollack, M., Jollet, F., Thromat, N., and Gautier-Soyer, M. (1995) X-ray-absorption spectroscopy at the iron L2,3 threshold in iron oxides. Physical Review B, 52, 3143–3150.10.1103/PhysRevB.52.3143Search in Google Scholar PubMed
de Groot, F.M.F. (2005) 1s2p resonant inelastic X-ray scattering of iron oxides. Journal of Physical Chemistry B, 109, 20751.10.1021/jp054006sSearch in Google Scholar PubMed
de Groot, F.M.F., Fuggle, J.C., Thole, B.T., and Sawatzky, G.A. (1990) 2p X-ray absorption of 3d transition metal compounds: An atomic multiplet description including the crystal field. Physical Review B, 42, 5459–5468.10.1103/PhysRevB.42.5459Search in Google Scholar
de Smit, E., Creemer, J.F., Zandbergen, H.W., Weckhuysen, B.M., and de Groot, F.M.F. (2009) In-situ scanning transmission X-ray microscopy of catalytic materials under reaction conditions. Journal of Physics: Conference Series, 190, 1–4.10.1088/1742-6596/190/1/012161Search in Google Scholar
Dynes, J.J., Tyliszczak, T., Araki, T., Lawrence, J.R., Swerhone, G.D.W., Leppard, G.G., and Hitchcock, A.P. (2006) Speciation and quantitative mapping of metal species in microbial biofilms using scanning transmission X-ray microscopy. Environmental Science & Technology, 40, 1556–1565.10.1021/es0513638Search in Google Scholar
Fleet, M.E. (1986) The structure of magnetite: symmetry of cubic spinels. Journal of Solid State Chemistry, 62, 75–82.10.1016/0022-4596(86)90218-5Search in Google Scholar
Gilbert, B., Kim, C.S., Dong, C.-L., Guo, J., Nico, P.S., and Shuh, D.K. (2007) Oxygen K-edge emission and absorption spectroscopy of iron oxyhydroxide nanoparticles. AIP Conference Proceedings, 882, 721–725.10.1063/1.2644643Search in Google Scholar
Gilbert, B., Katz, K.E., Denlinger, J.D., Yin, Y., Falcone, R., and Waychunas, G.A. (2010) Soft X-ray spectroscopy study of the electronic structure of oxidized and partially oxidized magnetite nanoparticles. Journal of Physical Chemistry C, 114, 21994–22001.10.1021/jp106919aSearch in Google Scholar
Gilbert, B., Erbs, J.J., Penn, R.L., Petkov, V., Spagnoli, D., and Waychunas, G.A. (2013) A disordered nanoparticle model for 6-line ferrihydrite. American Mineralogist, 98, 1465–1476.10.2138/am.2013.4421Search in Google Scholar
Grandjean, F., Waddill, G.D., Cummins, T.R., Moore, D.P., Long, G.J., and Buschow, K.H.J. (1999) A cerium M-edge X-ray absorption and an iron L-edge magnetic circular dichroism study of the Ce2Fe17−xMx solid solutions, where M is Al and Si. Solid State Communications, 109, 779–784.10.1016/S0038-1098(98)00623-1Search in Google Scholar
Gualtieri, A.F., and Venturelli, P. (1999) In situ study of the goethite-hematite phase transformation by real time synchrotron powder diffraction. American Mineralogist, 84, 895–904.10.2138/am-1999-5-624Search in Google Scholar
Guyodo, Y., Sainctavit, P., Arrio, M.A., Carvallo, C., Penn, R.L., Erbs, J.J., Forsberg, B.S., Morin, G., Maillot, F., Lagroix, F., and Bonville, P. (2012) X-ray magnetic circular dichroïsm provides strong evidence for tetrahedral iron in ferrihydrite. Geochemistry, Geophysics, Geosystems, 13, 1–9.10.1029/2012GC004182Search in Google Scholar
Hitchcock, A.P. (2008) aXis2000 is written in interactive data language (IDL) and is freely available online for non-commercial use. http://unicorn.mcmaster.ca/aXis2000.html.Search in Google Scholar
Hochella, M.F., Moore, J.N., Putnis, C.V., Putnis, A., Kasama, T., and Eberl, D.D. (2005) Direct observation of heavy metal-mineral association from the Clark Fork River superfund complex: Implications for metal transport and bioavailability. Geochimica et Cosmochimica Acta, 69, 1651–1663.10.1016/j.gca.2004.07.038Search in Google Scholar
Hocking, R.K., George, S.D., Raymond, K.N., Hodgson, K.O., Hedman, B., and Solomon, E.I. (2010) Fe L-edge X-ray absorption spectroscopy determination of differential orbital covalency of siderophore model compounds: Electronic structure contributions to high stability constants. Journal of the American Chemical Society, 132, 4006–4015.10.1021/ja9090098Search in Google Scholar
Jambor, J.L., and Dutrizac, J.E. (1998) The occurrence and constitution of natural and synthetic ferrihydrite, a widespread iron oxyhydroxide. Chemical Reviews, 98, 2549–2585.10.1021/cr970105tSearch in Google Scholar
Janney, D.E., Cowley, J.M., and Buseck, P.R. (2001) Structure of synthetic 6-line ferrihydrite by electron nanodiffraction. American Mineralogist, 86, 327–335.10.2138/am-2001-2-316Search in Google Scholar
Kendelewicz, T., Liu, P., Doyle, C.S., and Brown, G.E. (2000) Spectroscopic study of the reaction of aqueous Cr(VI) with Fe3O4 (111) surfaces. Surface Science, 469, 144–163.10.1016/S0039-6028(00)00808-6Search in Google Scholar
Krueger, B.J., Grassian, V.H., Cowin, J.P., and Laskin, A. (2004) Heterogeneous chemistry of individual mineral dust particles from different dust source regions: The importance of particle mineralogy. Atmospheric Environment, 38, 6253–6261.10.1016/j.atmosenv.2004.07.010Search in Google Scholar
Labatut, C., Berjoan, R., Armas, B., Shamm, S., Sevely, J., Riog, A., and Molins, E. (1998) Studies of LPCVD Al–Fe–O deposits by XPS, EELS and Mössbauer spectroscopies. Surface and Coatings Technology, 105, 31–37.10.1016/S0257-8972(97)00562-8Search in Google Scholar
Lead, J.R., and Wilkinson, K.J. (2006) Aquatic colloids and nanoparticles: Current knowledge and future trends. Environmental Chemistry, 3, 159–171.10.1071/EN06025Search in Google Scholar
Liu, H.C., Xia, J.L., Nie, Z.Y., Zheng, L., Hong, C.H., and Zhao, Y.D. (2015) Iron L-edge and sulfur K-edge XANES spectroscopy analysis of pyrite leached by Acidianus manzaensis. Transactions of the Nonferrous Metals Society of China, 25, 2407–2414.10.1016/S1003-6326(15)63856-0Search in Google Scholar
Majestic, B.J., Schauer, J.J., and Shafer, M.M. (2007) Application of synchrotron radiation for measurement of iron redox speciation in atmospherically processed aerosols. Atmospheric Chemistry and Physics, 7, 2475–2487.10.5194/acp-7-2475-2007Search in Google Scholar
Makovicky, E., and Balić-Žunić, T. (1998) New measure of distortion for coordination polyhedra. Acta Crystallographica, B54, 766–773.10.1107/S0108768198003905Search in Google Scholar
Manceau, A. (2012) Comment on “Direct observation of tetrahedrally coordinated Fe(III) in ferrihydrite.” Environmental Science & Technology, 46, 6882–6884.10.1021/es3011749Search in Google Scholar PubMed
Michel, F.M., Ehm, L., Antao, S.M., Lee, P.L., Chupas, P.J., Liu, G., Strongin, D.R., Schoonen, M.A.A., Phillips, B.L., and Parise, J.B. (2007) The structure of ferrihydrite, a nanocrystalline material. Science, 316, 1726–1729.10.1126/science.1142525Search in Google Scholar PubMed
Miedema, P.S., and de Groot, F.M.F. (2013) Fe 2p X-ray absorption and electron energy loss spectroscopy. Journal of Electron Spectroscopy and Related Phenomena, 187, 32–48.10.1016/j.elspec.2013.03.005Search in Google Scholar
Mikhlin, Y., Tomashevich, Y., Tauson, V., Vyalikh, D., Molodtsov, S., and Szargan, R. (2005) A comparative X-ray absorption near-edge structure study of bornite, Cu5FeS4, and chalcopyrite, CuFeS2. Journal of Electron Spectroscopy and Related Phenomena, 142, 83–88.10.1016/j.elspec.2004.09.003Search in Google Scholar
Miot, J., Benzerara, K., Morin, G., Kappler, A., Bernard, S., Obst, M., Férard, C., Skouri-Panet, F., Guigner J.-M., Posth, N., and others. (2009) Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria. Geochimica et Cosmochimica Acta, 73, 696–711.10.1016/j.gca.2008.10.033Search in Google Scholar
Miyajima, N., Langenhorst, F., Frost, D.J., and Yagi, T. (2004) Electron channeling spectroscopy of iron in majoritic garnet and silicate perovskite using a transmission electron microscope. Physics of the Earth and Planetary Interiors, 143-144, 601–609.10.1016/j.pepi.2003.07.023Search in Google Scholar
Padmore, H.A., and Warwick, T. (1994) Soft X-ray monochromators for third-generation undulator sources. Journal of Synchrotron Radiation, 1, 27–36.10.1107/S0909049594007041Search in Google Scholar PubMed
Peak, D., and Regier, T. (2012) Direct observation of tetrahedrally co-ordinated Fe(III) in ferrihydrite. Environmental Science & Technology, 46, 3163–3168.10.1021/es203816xSearch in Google Scholar PubMed
Post, J.E., and Buchwald, V.F. (1991) Crystal structure refinement of akaganeite. American Mineralogist, 76, 272–277.Search in Google Scholar
Regan, T.J., Ohldag, H., Stamm, C., Nolting, F., Lüning, J., Stöhr, J., and White, R.L. (2001) Chemical effects at metal oxide interfaces studied by X-ray-absorption spectroscopy. Physical Review B, 64, 1–11.10.1103/PhysRevB.64.214422Search in Google Scholar
Ressler, T. (1998) WinXAS: A program for X-ray absorption spectroscopy data analysis under MS-windows. Journal of Synchrotron Radiation, 5, 118.10.1107/S0909049597019298Search in Google Scholar PubMed
Robinson, K., Gibbs, G.V., and Ribbe, P.H. (1971) A quadratic measure of distortion in coordination polyhedra. Science, 172, 567–570.10.1126/science.172.3983.567Search in Google Scholar PubMed
Schofield, P.F., Henderson, C.M.B., Cressey, G., and van der Laan, G. (1995) 2p X-ray absorption spectroscopy in the Earth sciences. Journal of Synchrotron Radiation, 2, 93–98.10.1107/S0909049595000598Search in Google Scholar PubMed
Schwertmann, U., and Cornell, R.M. (2000) Iron Oxides in the Laboratory: Preparation and characterization. 2nd ed., p. 67–143. Wiley.10.1002/9783527613229.ch05Search in Google Scholar
Sherman, D.M. (1985a) The electronic structure of Fe3+ coordination sites in iron oxides; applications to spectra, bonding and magnetism. Physics and Chemistry of Minerals, 12, 161–175.10.1007/BF00308210Search in Google Scholar
Sherman, D.M. (1985b) SCF-Xα-SW MO study of Fe-O and Fe-OH chemical bonds; Applications to the Mössbauer spectra and the magnetochemistry of hydroxylbearing Fe3+ oxides and silicates. Physics and Chemistry of Minerals, 12, 311–314.10.1007/BF00310345Search in Google Scholar
Sherman, D.M. (2005) Electronic structures of iron(III) and manganese(IV) (hydr) oxide minerals: Thermodynamics of photochemical reductive dissolution in aquatic environments. Geochimica et Cosmochimica Acta, 69, 3249–3255.10.1016/j.gca.2005.01.023Search in Google Scholar
Sherman, D.M., and Waite, T.D. (1985) Electronic spectra of Fe3+ oxides and oxide hydroxides in the near IR to near UV. American Mineralogist, 70, 1262–1269.Search in Google Scholar
Shirakawa, J., Nakayama, M., Wakihara, M., and Uchimoto, Y. (2007) Changes in electronic structure upon lithium insertion into Fe2(SO4)3 and Fe2(MoO4)3 investigated by X-ray absorption spectroscopy. The Journal of Physical Chemistry B, 111, 1424–1430.10.1021/jp065802gSearch in Google Scholar PubMed
Shmakov, A.N., Kryukova, G.N., Tsybulya, S.V., Chuvilin, A.L., and Solovyeva, L.P. (1995) Vacancy ordering in-Fe2O3: Synchrotron X-ray powder diffraction and high-resolution electron microscopy studies. Journal of Applied Crystallography, 28, 141–145.10.1107/S0021889894010113Search in Google Scholar
Stavitski, E., and De Groot, F.M. (2010) The CTM4XAS program for EELS and XAS spectral shape analysis of transition metal L edges. Micron, 41, 687–694.10.1016/j.micron.2010.06.005Search in Google Scholar PubMed
Takahama, S., Gilardoni, S., and Russell, L.M. (2008) Single-particle oxidation state and morphology of atmospheric iron aerosols. Journal of Geophysical Research, 113, 1–16.10.1029/2008JD009810Search in Google Scholar
Todd, E.C., Sherman, D.M., and Purton, J.A. (2003a) Surface oxidation of pyrite under ambient atmospheric and aqueous (pH=2-10) conditions: Electronic structure and mineralogy from X-ray absorption spectroscopy. Geochimica et Cosmochimica Acta, 67, 881–893.10.1016/S0016-7037(02)00957-2Search in Google Scholar
Toner, B.M., Fakra, S.C., Manganini, S.J., Santelli, C.M., Marcus, M.A., Moffett, J.W., Rouxel, O., German, C.R., and Edwards, K.J. (2009) Preservation of iron (II) by carbon-rich matrices in a hydrothermal plume. Nature Geoscience, 2, 197–201.10.1038/ngeo433Search in Google Scholar
Tossell, J.A., Vaughan, D.J., and Johnson, K.H. (1974) The electronic structure of rutile, wustite and hematite from molecular orbital calculations. American Mineralogist, 59, 319–334.Search in Google Scholar
van Aken, P.A., and Liebscher, B. (2002) Quantification of ferrous/ferric ratios in minerals: New evaluation schemes of Fe L2,3 electron energy-loss near-edge spectra. Physics and Chemistry of Minerals, 28, 188–200.10.1007/s00269-001-0222-6Search in Google Scholar
van Aken, P.A., Liebscher, B., and Styrsa, V.J. (1998) Quantitative determination of iron oxidation states in minerals using Fe L2,3-edge electron energy-loss nearedge structure spectroscopy. Physics and Chemistry of Minerals, 25, 323–327.10.1007/s002690050122Search in Google Scholar
van der Laan, G., and Kirkman, I.W. (1992) The 2p absorption spectra of 3d transition metal compounds in tetrahedral and octahedral symmetry. Journal of Physics: Condensed Matter, 4, 4189–4204.Search in Google Scholar
Vaughan, D.J., Tossell, J.A., and Johnson, K.H. (1974) The bonding of ferrous iron to sulphur and oxygen in tetrahedral coordination: a comparative study using SCF Xa scattered wave molecular orbital calculations. Geochimica et Cosmochimica Acta, 38, 993–1005.10.1016/0016-7037(74)90001-5Search in Google Scholar
Von der Heyden, B.P., and Roychoudhury, A.N. (2015) Application, chemical interaction and fate of iron minerals in polluted sediment and soils. Current Pollution Reports, 1(4), 1–15.10.1007/s40726-015-0020-2Search in Google Scholar
Von der Heyden, B.P., Roychoudhury, A.N., Mtshali, T.N., Tyliszczak, T., and Myneni, S.C.B. (2012) Chemically and geographically distinct solid-phase iron pools in the Southern Ocean. Science, 338, 1199–1201.10.1126/science.1227504Search in Google Scholar PubMed
Von der Heyden, B.P., Hauser, E.J., Mishra, B., Martinez, G.A., Bowie, A.R., Tyliszczak, T., Roychoudhury, A.N., and Myneni, S.C.B. (2014) Ubiquitous presence of Fe(II) in aquatic colloids and its association with organic carbon. Environmental Science & Technology Letters, 1, 387–392.10.1021/ez500164vSearch in Google Scholar
Wang, H., Peng, G., Miller, L.M., Scheuring, E.M., George, S.J., Chance, M.R., and Cramer, S.P. (1997) Iron L-edge X-ray absorption spectroscopy of myoglobin complexes and photolysis products. Journal of the American Chemical Society, 119, 4921–4928.10.1021/ja961446bSearch in Google Scholar
Welsh, I.D., and Sherwood, P.M.A. (1989) Photoemission and electronic structure of FeOOH: Distinguishing between oxide and hydroxide. Physical Review B, 40, 6386–6392.10.1103/PhysRevB.40.6386Search in Google Scholar
Wiggington, N.S., Haus, K.L., and Hochella, M.F. (2007) Aquatic environmental nanoparticles. Journal of Environmental Monitoring, 9, 1306–1316.10.1039/b712709jSearch in Google Scholar PubMed
Wycoff, R.W.G. (1963) Crystal Structures, 2nd ed., p. 290–295. Interscience, New York.Search in Google Scholar
Zhu, X., Kalirai, S.S., Hitchcock, A.P., and Bazylinski, D.A. (2015) What is the correct Fe L23 X-ray absorption spectrum of magnetite? Journal of Electron Spectroscopy and Related Phenomena, 199, 19–26.10.1016/j.elspec.2014.12.005Search in Google Scholar
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