High-Pressure Chemistry of Hydrogen in Metals: In Situ Study of Iron Hydride

1991/07/26 by John V. Badding, R. J. Hemley, H. K. Mao · 6 citations
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Advanced Chemical Physics Studies #High-pressure geophysics and materials #Nuclear Materials and Properties

paper · doi:10.1126/science.253.5018.421

openalex publication_date 1991/07/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/27

Abstract

Optical observations and x-ray diffraction measurements of the reaction between iron and hydrogen at high pressure to form iron hydride are described. The reaction is associated with a sudden pressure-induced expansion at 3.5 gigapascals of iron samples immersed in fluid hydrogen. Synchrotron x-ray diffraction measurements carried out to 62 gigapascals demonstrate that iron hydride has a double hexagonal close-packed structure, a cell volume up to 17% larger than pure iron, and a stoichiometry close to FeH. These results greatly extend the pressure range over which the technologically important iron-hydrogen phase diagram has been characterized and have implications for problems ranging from hydrogen degradation and embrittlement of ferrous metals to the presence of hydrogen in Earth's metallic core.

Citations

• Diamond anvil cell and high-pressure physical investigations
• Calibration of the ruby pressure gauge to 800 kbar under quasi‐hydrostatic conditions

Cited by

• X-ray diffraction and Mössbauer spectroscopy study of fcc iron hydride FeH at high pressures and implications for the composition of the Earth's core
• Hydrogen Partitioning into Molten Iron at High Pressure: Implications for Earth's Core
• Neutron diffraction investigation of the dhcp and hcp iron hydrides and deuterides
• Formation of iron hydride and high-magnetite at high pressure and temperature
• Fe-H melting curve below 3 GPa: Implications for hydrogen in the lunar core
• Iron–hydrogen alloy [wikipedia]
• Iron hydride [wikipedia]