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Title: Structural complexity of simple Fe 2O 3 at high pressures and temperatures

Although chemically very simple, Fe 2O 3 is known to undergo a series of enigmatic structural, electronic and magnetic transformations at high pressures and high temperatures. So far, these transformations have neither been correctly described nor understood because of the lack of structural data. Here we report a systematic investigation of the behaviour of Fe 2O 3 at pressures over 100 GPa and temperatures above 2,500 K employing single crystal X-ray diffraction and synchrotron Mössbauer source spectroscopy. Crystal chemical analysis of structures presented here and known Fe(II, III) oxides shows their fundamental relationships and that they can be described by the homologous series nFeO·mFe 2O 3. Decomposition of Fe 2O 3 and Fe 3O 4 observed at pressures above 60 GPa and temperatures of 2,000 K leads to crystallization of unusual Fe 5O 7 and Fe 25O 32 phases with release of oxygen. Lastly, our findings suggest that mixed-valence iron oxides may play a significant role in oxygen cycling between earth reservoirs.
Authors:
 [1] ;  [1] ;  [1] ; ORCiD logo [1] ; ORCiD logo [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [5]
  1. Univ. of Bayreuth, Bayreuth (Germany)
  2. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
  3. Univ. of Bayreuth, Bayreuth (Germany); European Synchrotron Radiation Facility, Grenoble (France)
  4. European Synchrotron Radiation Facility, Grenoble (France)
  5. Univ. of Chicago, Argonne, IL (United States)
Publication Date:
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal Issue: 02, 2016; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; chemical physics; structural properties
OSTI Identifier:
1238292