TY - JOUR
T1 - Greigite (Fe3S4) is thermodynamically stable
T2 - Implications for its terrestrial and planetary occurrence
AU - Subramani, Tamilarasan
AU - Lilova, Kristina
AU - Abramchuk, Mykola
AU - Leinenweber, Kurt D.
AU - Navrotsky, Alexandra
N1 - Funding Information:
ACKNOWLEDGMENTS. This study was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division under Award DE-FG02-97ER14749.
Publisher Copyright:
© 2020 National Academy of Sciences. All rights reserved.
PY - 2020/11/17
Y1 - 2020/11/17
N2 - Iron sulfide minerals are widespread on Earth and likely in planetary bodies in and beyond our solar system. Using measured enthalpies of formation for three magnetic iron sulfide phases: bulk and nanophase Fe3S4 spinel (greigite), and its high-pressure monoclinic phase, we show that greigite is a stable phase in the Fe–S phase diagram at ambient temperature. The thermodynamic stability and low surface energy of greigite supports the common occurrence of fine-grained Fe3S4 in many anoxic terrestrial settings. The high-pressure monoclinic phase, thermodynamically metastable below about 3 GPa, shows a calculated negative P-T slope for its formation from the spinel. The stability of these three phases suggests their potential existence on Mercury and their magnetism may contribute to its present magnetic field.
AB - Iron sulfide minerals are widespread on Earth and likely in planetary bodies in and beyond our solar system. Using measured enthalpies of formation for three magnetic iron sulfide phases: bulk and nanophase Fe3S4 spinel (greigite), and its high-pressure monoclinic phase, we show that greigite is a stable phase in the Fe–S phase diagram at ambient temperature. The thermodynamic stability and low surface energy of greigite supports the common occurrence of fine-grained Fe3S4 in many anoxic terrestrial settings. The high-pressure monoclinic phase, thermodynamically metastable below about 3 GPa, shows a calculated negative P-T slope for its formation from the spinel. The stability of these three phases suggests their potential existence on Mercury and their magnetism may contribute to its present magnetic field.
KW - Greigite | thermodynamic stability | terrestrial planets | magnetism | high pressure
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U2 - 10.1073/pnas.2017312117
DO - 10.1073/pnas.2017312117
M3 - Article
C2 - 33139534
AN - SCOPUS:85096356430
SN - 0027-8424
VL - 117
SP - 28645
EP - 28648
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 46
ER -