We observed a direct reaction of metallic iron with water to form iron hydride and iron oxide, 3Fe + H2O->2FeHx + FeO, at pressures from 6 GPa to 84 GPa and temperatures above 1,000 K in diamond anvil cell (DAC). Iron hydride is dhcpFeHx or γ-FeHx, and iron oxide has the rhombohedral or B1 structure at pressures at least up to 37 GPa. The formation of an assembly composed of dhcpFeHx and FeO with the B8 structure was observed at 84 GPa. In primordial Earth, water formed by dehydration of the low temperature primitive materials reacts with metallic iron in the high temperature component to form iron hydride FeHx and iron oxide FeO. The former would be incorporated in the iron forming the core. Thus hydrogen could be an important element of the Earth's core. This reaction would be essential for transport of hydrogen into the core in the accretion stage of the Earth.
|ジャーナル||Physics and Chemistry of Minerals|
|出版ステータス||Published - 2005 5月 1|
ASJC Scopus subject areas