| Autor: |
Ubukata H; Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan., Kato D; Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan., Kitade S; Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan., Broux T; Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan., Tassel C; Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan., Schnieders D; Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, D-52056 Aachen, Germany., Dronskowski R; Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, D-52056 Aachen, Germany.; Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, 7098 Liuxian Boulevard, Nanshan District, Shenzhen 518055, China., Kageyama H; Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan. |
| Abstrakt: |
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 ChLn 6 octahedra is stabilized over the 1H structure with ChLn 6 trigonal prisms due to relatively small electrostatic repulsion, supported by analysis of Madelung energy, crystal orbital Hamilton population (COHP), and density of energy (DOE). |
