High-Pressure Polymorphs of LaHO with Anion Coordination Reversal.
Journal of the American Chemical Society
American Chemical Society
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Broux, T., Ubukata, H., Pickard, C., Takeiri, F., Kobayashi, G., Kawaguchi, S., Yonemura, M., et al. (2019). High-Pressure Polymorphs of LaHO with Anion Coordination Reversal.. Journal of the American Chemical Society, 141 (22), 8717-8720. https://doi.org/10.1021/jacs.9b03320
Two novel high-pressure polymorphs of lantha- num oxyhydride have been successfully predicted and stabilized under pressure. When reacted at 3 GPa, the fluorite structure of LaHO with anion-centered tetrahedral (HLa4/OLa4) geometry is transformed to the PbCl2-type structure involving coordination number increase of H– to five (HLa5 square pyramids). Upon fur- ther application of pressure to 5 GPa, LaHO changed into the anti Fe2P-type structure. Interestingly, the 5 GPa phase contains tetra- hedral HLa4 and square-pyramidal OLa5 geometry, meaning co- ordination switching, as confirmed by ab initio calculations. The structural analysis shows that this unprecedented phenomenon is enabled by higher compressibility of hydride anion and emphasiz- es its potential in the search for new high-pressure forms of hy- dride-based materials.
Royal Society (WM150023)
External DOI: https://doi.org/10.1021/jacs.9b03320
This record's URL: https://www.repository.cam.ac.uk/handle/1810/292999
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