The orthorhombic structure of iron: An in situ study at high-temperature and high-pressure

An in situ angle-dispersive x-ray diffraction study was undertaken of iron in a laser-heated, diamond-anvil cell up to 2375 kelvin and between 30 and 100 gigapascals in Al2O3-and SiO2-pressure media. The resolution and reliability of diffraction peak intensities allow quantitative assessment of a structural model. The results confirm that iron undergoes a phase transformation at high pressures and temperatures. The space group is Pbcm for an orthorhombic lattice, and the atomic topology is close to that of epsilon hexagonal close-packed iron.