Greigite (Fe₃S₄) is thermodynamically stable: Implications for its terrestrial and planetary occurrence.

ABSTRACT: 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 an

SUBMITTER: Subramani T 

PROVIDER: S-EPMC7682356 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature