skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Altered chemistry of oxygen and iron under deep Earth conditions

Abstract

A drastically altered chemistry was recently discovered in the Fe-O-H system under deep Earth conditions, involving the formation of iron superoxide (FeO 2Hx with x =0 to 1), but the puzzling crystal chemistry of this system at high pressures is largely unknown. Here we present evidence that despite the high O/Fe ratio in FeO 2Hx, iron remains in the ferrous, spin-paired and non-magnetic state at 60–133 GPa, while the presence of hydrogen has minimal effects on the valence of iron. The reduced iron is accompanied by oxidized oxygen due to oxygen-oxygen interactions. The valence of oxygen is not –2 as in all other major mantle minerals, instead it varies around –1. This result indicates that like iron, oxygen may have multiple valence states in our planet’s interior. Laslty, our study suggests a possible change in the chemical paradigm of how oxygen, iron, and hydrogen behave under deep Earth conditions.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [3]; ORCiD logo [4];  [5];  [5];  [5];  [6];  [7];  [8]
  1. Center for High Pressure Science and Technology Advanced Research, Beijing (China); Stanford Univ., CA (United States)
  2. Center for High Pressure Science and Technology Advanced Research, Beijing (China)
  3. Argonne National Lab. (ANL), Argonne, IL (United States); University of Illinois at Urbana-Champaign, Urbana, IL (United States)
  4. Carnegie Inst. of Washington, Washington, DC (United States)
  5. Argonne National Lab. (ANL), Argonne, IL (United States)
  6. Univ. of Chicago, IL (United States)
  7. Center for High Pressure Science and Technology Advanced Research, Beijing (China); Carnegie Inst. of Washington, Washington, DC (United States)
  8. Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Science Foundation (NSF); National Natural Science Foundation of China (NNSFC)
OSTI Identifier:
1493416
Alternate Identifier(s):
OSTI ID: 1493910
Grant/Contract Number:  
AC02-76SF00515; FG02-99ER45775; FG02-94ER14466; AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 10; Journal Issue: 1; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 58 GEOSCIENCES

Citation Formats

Liu, Jin, Hu, Qingyang, Bi, Wenli, Yang, Liuxiang, Xiao, Yuming, Chow, Paul, Meng, Yue, Prakapenka, Vitali B., Mao, Ho-Kwang, and Mao, Wendy L. Altered chemistry of oxygen and iron under deep Earth conditions. United States: N. p., 2019. Web. doi:10.1038/s41467-018-08071-3.
Liu, Jin, Hu, Qingyang, Bi, Wenli, Yang, Liuxiang, Xiao, Yuming, Chow, Paul, Meng, Yue, Prakapenka, Vitali B., Mao, Ho-Kwang, & Mao, Wendy L. Altered chemistry of oxygen and iron under deep Earth conditions. United States. doi:10.1038/s41467-018-08071-3.
Liu, Jin, Hu, Qingyang, Bi, Wenli, Yang, Liuxiang, Xiao, Yuming, Chow, Paul, Meng, Yue, Prakapenka, Vitali B., Mao, Ho-Kwang, and Mao, Wendy L. Fri . "Altered chemistry of oxygen and iron under deep Earth conditions". United States. doi:10.1038/s41467-018-08071-3. https://www.osti.gov/servlets/purl/1493416.
@article{osti_1493416,
title = {Altered chemistry of oxygen and iron under deep Earth conditions},
author = {Liu, Jin and Hu, Qingyang and Bi, Wenli and Yang, Liuxiang and Xiao, Yuming and Chow, Paul and Meng, Yue and Prakapenka, Vitali B. and Mao, Ho-Kwang and Mao, Wendy L.},
abstractNote = {A drastically altered chemistry was recently discovered in the Fe-O-H system under deep Earth conditions, involving the formation of iron superoxide (FeO2Hx with x =0 to 1), but the puzzling crystal chemistry of this system at high pressures is largely unknown. Here we present evidence that despite the high O/Fe ratio in FeO2Hx, iron remains in the ferrous, spin-paired and non-magnetic state at 60–133 GPa, while the presence of hydrogen has minimal effects on the valence of iron. The reduced iron is accompanied by oxidized oxygen due to oxygen-oxygen interactions. The valence of oxygen is not –2 as in all other major mantle minerals, instead it varies around –1. This result indicates that like iron, oxygen may have multiple valence states in our planet’s interior. Laslty, our study suggests a possible change in the chemical paradigm of how oxygen, iron, and hydrogen behave under deep Earth conditions.},
doi = {10.1038/s41467-018-08071-3},
journal = {Nature Communications},
issn = {2041-1723},
number = 1,
volume = 10,
place = {United States},
year = {2019},
month = {1}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

Figures / Tables:

Fig. 1 Fig. 1: Representative XAS and XRS spectra of iron oxide compounds. a PFY-XAS spectra at Fe K-edge of iron oxide compounds at room temperature. Black, olive, blue, and cyan lines: Fe0, Fe2+O, Fe3+2O3, and CaFe4+O3 at ambient conditions, respectively; light and dark magenta lines: Py-FeO2 at 53 and 81 GPa,more » respectively; red line: Py-FeO2Hx at 133 GPa; gray arrow: the link from the dashed outline to the inset. Inset: the area zoomed for the dashed outline in Fig. 1a. b XRS spectra of Py-FeO2Hx at 110 GPa. Circles: experimental data; shaded areas: fitted peaks« less

Save / Share:

Works referenced in this record:

Unraveling the complexity of iron oxides at high pressure and temperature: Synthesis of Fe5O6
journal, June 2015

  • Lavina, Barbara; Meng, Yue
  • Science Advances, Vol. 1, Issue 5, Article No. e1400260
  • DOI: 10.1126/sciadv.1400260

    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.