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Published on: May 20, 2018
Absence of pressure-induced amorphization in LiKSO4
D Machon1, C B Pinheiro, P Bouvier
1Laboratoire PMCN, CNRS, Université de Lyon 1, UMR 5586, F-69622 Villeurbanne Cedex, France. denis.machon@lpmcn.univ-lyon1.fr
Summary
Lithium potassium sulfate (LiKSO(4)) crystals undergo three distinct phase transitions under high pressure, as revealed by synchrotron radiation diffraction. Contrary to prior research, no amorphous phase formed even at 24 GPa.
Area of Science:
- Solid-state chemistry
- Materials science under extreme conditions
- Crystallography
Background:
- Understanding phase transitions in crystalline materials is crucial for predicting their behavior under varying conditions.
- Lithium potassium sulfate (LiKSO(4)) is a material with potential applications, necessitating a thorough investigation of its structural stability.
- Previous studies suggested the possibility of pressure-induced amorphization in LiKSO(4), requiring experimental verification.
Purpose of the Study:
- To investigate the high-pressure behavior of lithium potassium sulfate (LiKSO(4)) crystals.
- To identify and characterize the phase transitions occurring in LiKSO(4) under hydrostatic and non-hydrostatic pressure.
- To clarify the structural details of the high-pressure phases and assess the potential for amorphization.
Main Methods:
- Angle-resolved synchrotron radiation diffraction was employed to probe the crystal structure.
- Powder diffraction data were analyzed using Rietveld refinement techniques.
- High pressure was applied using specialized equipment to simulate extreme conditions.
Main Results:
- Three phase transitions were confirmed in LiKSO(4) at approximately 0.8 GPa (α→β), 4.0 GPa (β→γ), and 7.0 GPa (γ→δ).
- Two competing structures, orthorhombic (Cmc 2(1)) and monoclinic (Cc), were proposed for the β-phase.
- The γ-phase was indexed as monoclinic, and the δ-phase exhibited significant disorder. No amorphous phase was observed up to 24 GPa.
Conclusions:
- LiKSO(4) exhibits complex structural transformations under high pressure.
- The proposed structures for the β-phase align with models of low-temperature phases.
- The absence of pressure-induced amorphization under tested conditions contradicts previous hypotheses, highlighting the material's structural resilience.
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