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Updated: Aug 2, 2025
Hyperspectral Imaging as a Tool to Study Optical Anisotropy in Lanthanide-Based Molecular Single Crystals
Published on: April 14, 2020
Structural Transformation in LnHS (Ln = La, Nd, Gd, and Er) with Coordination Change between an S-Centered Octahedron
Hiroki Ubukata1, Daichi Kato1, Shougo Kitade1
1Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
Abstract:
Lanthanide hydride chalcogenides LnHSe and LnHTe (Ln = lanthanides) crystallize in two polymorphs, 2H and 1H structures (ZrBeSi-type and filled-WC-type structures, respectively), but the chemical origin of the structural selection is unknown. Here, we have expanded the LnHCh (Ch = O, Se, and Te) family to include LnHS (Ln = La, Nd, Gd, and Er) using high-pressure synthesis. LnHS adopts the 2H structure for large Ln (La, Nd, and Gd) and the 1H structure for small Er. We compared the two polymorphs using anion-centered polyhedra and found that in the compounds with large ionicity, the 2H structure with ChLn6 octahedra is stabilized over the 1H structure with ChLn6 trigonal prisms due to relatively small electrostatic repulsion, supported by analysis of Madelung energy, crystal orbital Hamilton population (COHP), and density of energy (DOE).
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