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High‐pressure polymorphism of Fe 2 P and its implications for meteorites and Earth's core
Author(s) -
Dera Przemyslaw,
Lavina Barbara,
Borkowski Lauren A.,
Prakapenka Vitali B.,
Sutton Stephen R.,
Rivers Mark L.,
Downs Robert T.,
Boctor Nabil Z.,
Prewitt Charles T.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl033867
Subject(s) - meteorite , earth (classical element) , astrobiology , outer core , chondrite , condensation , materials science , inner core , mineralogy , geology , thermodynamics , physics , geophysics , mathematical physics
Minerals with composition (Fe,Ni) 2 P, are rare, though important accessory phases in iron and chondritic meteorites. The occurrence of these minerals in meteorites is believed to originate either from the equilibrium condensation of protoplanetary materials in solar nebulae or from the later accretion and condensation processes in the cores of parent bodies. Fe‐Ni phosphides are considered a possible candidate for a minor phase present in the Earth's core, and at least partially responsible for the observed density deficit with respect to pure iron. We report results of high‐pressure high‐temperature X‐ray diffraction experiments with synthetic barringerite (Fe 2 P) up to 40 GPa and 1400 K. A new phase transition to the Co 2 Si‐type structure has been found at 8.0 GPa, upon heating. The high‐pressure phase can be metastably quenched to ambient conditions at room temperature, and then, if heated again, transforms back to barringerite, providing an important constraint on the thermodynamic history of meteorite.