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Kirsten M. Ø. Jensen,†,‡ Henrik L. Andersen,† Christoffer Tyrsted,† Espen D. Bøjesen,† Ann-Christin Dippel,§ Nina Lock,† Simon J. L. Billinge,‡, Bo B. Iversen,*,† and Mogens Christensen*,†
ARTICLE
Mechanisms for Iron Oxide Formation under Hydrothermal Conditions: An in Situ Total Scattering Study †
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Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark, ‡Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States, §Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany, and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
ABSTRACT The formation and growth of maghemite (γ-Fe2O3) nanoparticles from ammonium
iron(III) citrate solutions (C6O7H6 3 xFe3þ 3 yNH4) in hydrothermal synthesis conditions have been
studied by in situ total scattering. The local structure of the precursor in solution is similar to that of the crystalline coordination polymer [Fe(H2cit(H2O)]n, where corner-sharing [FeO6] octahedra are
linked by citrate. As hydrothermal treatment of the solution is initiated, clusters of edge-sharing [FeO6] units form (with extent of the structural order
