Phase transition boundary between B1 and B8 structures of FeO up to 210GPa

Haruka Ozawa, Kei Hirose, Shigehiko Tateno, Nagayoshi Sata, Yasuo Ohishi

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    60 Citations (Scopus)


    We have determined the phase transition boundary between NaCl-type (B1) and NiAs-type (B8) structures of FeO up to 208. GPa and 3800. K on the basis of synchrotron X-ray diffraction (XRD) measurements in situ at high pressure and temperature using a laser-heated diamond-anvil cell (DAC). The boundary is located at 200. GPa and 3200. K with positive Clapeyron slope. These results show that B1 phase of FeO is stable along the whole mantle geotherm, whereas B8 phase is stabilized at the inner core condition. Additionally, FeO coexisted with metallic Fe in the present experiments. We found that hexagonal close-packed (hcp) iron is stable over the entire present experimental conditions. Moreover, the direct chemical analyses of the recovered sample demonstrated that solid iron did not contain any detectable oxygen. While extensive solid solution between Fe and FeO has been speculated above 60-80. GPa, the present results strongly suggest that the system Fe-FeO is simple eutectic at least to 200. GPa pressure range.

    Original languageEnglish
    Pages (from-to)157-163
    Number of pages7
    JournalPhysics of the Earth and Planetary Interiors
    Issue number3-4
    Publication statusPublished - Apr 2010


    • B1 structure
    • B8 structure
    • DAC
    • Hcp-iron
    • Phase transition
    • X-ray diffraction

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Geophysics
    • Physics and Astronomy (miscellaneous)
    • Space and Planetary Science


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