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Updated: Jan 25, 2026
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XAS studies of pressure-induced structural and electronic transformations in α-FeOOH
Summary
High pressure transforms iron oxyhydroxide (α-FeOOH goethite) by symmetrizing octahedra and inducing a high-to-low spin transition in iron. X-ray absorption spectroscopy confirms these structural and electronic changes.
Area of Science:
- Materials Science
- Geophysics
- Solid State Physics
Background:
- α-FeOOH goethite is an iron oxyhydroxide with a known crystal structure.
- Understanding its behavior under extreme conditions is crucial for various scientific fields.
Purpose of the Study:
- To investigate the structural and electronic transformations in α-FeOOH goethite under high pressure.
- To explore the pressure-induced spin transition of Fe³⁺ ions.
Main Methods:
- Fe K-edge x-ray absorption spectroscopy was employed.
- Experiments were conducted at pressures up to 50 GPa.
Main Results:
- Symmetrization of FeO₆ octahedra was observed.
- A high-to-low spin transition of Fe³⁺ occurred at pressures above approximately 45 GPa.
- Results align with single crystal XRD and Mössbauer spectroscopy data.
Conclusions:
- High pressure drives significant structural and electronic changes in α-FeOOH goethite.
- The observed spin crossover is linked to H-bond symmetrization.
- X-ray absorption spectroscopy is a valuable tool for studying H-bond symmetrization.
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