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Published on: June 7, 2018
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Metastable disordered phase in flash-frozen Prussian Blue analogues
Yevheniia Kholina1, Janine Dössegger2, Mads C Weber3
1Department of Materials, ETH Zürich, 8093 Zürich, Switzerland.
Summary
Researchers discovered a new metastable phase in flash-frozen Prussian blue analogues. This phase involves changes in symmetry and structure, likely due to confined water freezing within the material.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Crystallography
Background:
- Prussian blue analogues (PBAs) are versatile coordination compounds with diverse applications.
- Understanding the structural dynamics of PBAs under different conditions is crucial for their optimal use.
- Disordered PBAs present unique challenges and opportunities for materials innovation.
Purpose of the Study:
- To report the discovery and characterization of a novel metastable phase in flash-frozen disordered Prussian blue analogues.
- To investigate the structural and symmetry changes associated with this new phase.
- To elucidate the potential mechanism driving the formation of this metastable phase.
Main Methods:
- Flash-freezing of disordered Prussian blue analogues.
- X-ray diffraction (XRD) analysis to observe scattering patterns.
- Analysis of local structure symmetry and space groups.
- Characterization of phase transitions via translational modulation.
Main Results:
- Identification of a new metastable phase in flash-frozen disordered PBAs.
- Observed diffuse scattering clouds indicating structural disorder.
- Reduction in local structure symmetry from cubic to tetragonal or lower.
- Phase transition characterized by translational modulation of the structure.
Conclusions:
- The freezing of confined water within the PBA pores is the likely cause of the observed metastable phase.
- This discovery offers new insights into the phase behavior of PBAs under cryogenic conditions.
- The findings could influence the design and application of PBAs in fields requiring structural stability at low temperatures.
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