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

Journal Article · · Nature Communications
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)

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, spinpaired 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. Our study suggests a possible change in the chemical paradigm of how oxygen, iron, and hydrogen behave under deep Earth conditions.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
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 (NSFC)
Grant/Contract Number:
AC02-76SF00515; FG02-99ER45775; FG02-94ER14466; AC02-06CH11357
OSTI ID:
1493416
Alternate ID(s):
OSTI ID: 1493910
Journal Information:
Nature Communications, Vol. 10, Issue 1; ISSN 2041-1723
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 30 works
Citation information provided by
Web of Science

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Cited By (2)

Interaction Between FeOOH and NaCl at Extreme Conditions: Synthesis of Novel Na2FeCl4OHx Compound journal January 2020
Interaction Between FeOOH and NaCl at Extreme Conditions: Synthesis of Novel Na$_{2}$FeCl$_{4}$OH$_{x}$ Compound text January 2020

Figures / Tables (5)


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