The Ternary Gallide CeNiGa: Polymorphism and Hydrogen Absorption
In: Journal of Solid State Chemistry, Jg. 168 (2002-10-01), Heft 1, S. 28-33
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Zugriff:
The ternary gallide CeNiGa presents a crystallographic transformation with temperature. The crystal structure of the high-temperature form (HTF), determined for the first time by X-ray diffraction on a single crystal, is orthorhombic TiNiSi-type, whereas the low-temperature form (LTF) adopts the hexagonal ZrNiAl-type. Electrical resistivity and magnetization measurements reveal that both (LTF) and (HTF) CeNiGa are classified as intermediate valence compounds, but their Kondo temperatures TK are strongly different; TK≫300 K and TK≅95(5) K for (LTF) and (HTF), respectively. Both forms react with hydrogen at room temperature and form the hydride CeNiGaH1.1(1) which crystallizes in the hexagonal AlB2-type with lattice parameters a=4.239(4) A˚ and c=4.258(5) A˚. Hydrogenation also induces a valence transition for cerium from the intermediate valence state (CeNiGa) to a purely trivalent state (CeNiGaH1.1(1)). This behavior is correlated to an increase of the unit cell volume after hydrogenation and is compared to that observed previously for CeNiAlH1.93. [Copyright &y& Elsevier]
Titel: |
The Ternary Gallide CeNiGa: Polymorphism and Hydrogen Absorption
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Autor/in / Beteiligte Person: | Chevalier, B. ; Bobet, J. L. ; Gaudin, E. ; Pasturel, M. ; Etourneau, J. |
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Zeitschrift: | Journal of Solid State Chemistry, Jg. 168 (2002-10-01), Heft 1, S. 28-33 |
Veröffentlichung: | 2002 |
Medientyp: | academicJournal |
ISSN: | 0022-4596 (print) |
DOI: | 10.1006/jssc.2002.9671 |
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