Atomic-scale structure in alpha-FeOOH particles estimated from the anomalous X-ray scattering data with reverse Monte Carlo simulation

摘要

The realistic atomic-scale structure of synthesized alpha-FeOOH (goethite) particles, which is a typical ferric oxyhydroxide of corrosion product formed on the steel surface, has been estimated by fitting both the ordinary interference function and the environmental interference function obtained from the anomalous X-ray scattering (AXS) with model calculation using the reverse Monte Carlo (RMC) simulation technique. The results indicated that the FeO_6 octahedral unit structure is unchanged in a-FeOOH particles with and without chromium, but distortion of the linkage of FeO_6 octahedral unit structure is quite likely induced by chromium addition, where chromium is found to substitute for iron site in a-FeOOH particles. The middle-range ordering (approx ≈ nm scale) characterized by the FeO_6 octahedral unit structure in a-FeOOH particles was also visualized.