Crystal chemistry and thermodynamic properties of anisotropic Ce<subscript>2</subscript>Ni<subscript>7</subscript>H<subscript>4.7</subscript> hydride
In: Journal of Solid State Chemistry, Jg. 180 (2007-09-01), Heft 9, S. 2566-2576
Online
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Abstract: A new intermetallic deuteride Ce2Ni7D4.7 with an anomalous volume expansion has been studied. Its structure was solved on the basis of in situ neutron diffraction data. Expansion proceeds along the c-axis and within the CeNi2 slabs only. All D atoms are located inside these slabs and on the border between CeNi2 and CeNi5. Ordering of D atoms in the bulk of CeNi2 is accompanied by substantial deformation of these slabs thus lowering the hexagonal symmetry to orthorhombic [space group Pmcn (No. 62); a=4.9251(3)Å, b=8.4933(4)Å, c=29.773(1)Å]. Inside the CeNi2 layer the hydrogen sublattice is completely ordered; all D–D distances exceed 2.0Å. Local coordination of Ni by D inside the CeNi2 blocks is of “open”, saddle-like type. Hydrogen ordering is mainly determined by Ce–H and H–H interactions. The pressure–composition–temperature measurements yielded the following thermodynamic parameters of the formation of the hydride: ΔH=−22.4kJ/molH, ΔS=−59.9J/(KmolH). [Copyright &y& Elsevier]
Titel: |
Crystal chemistry and thermodynamic properties of anisotropic Ce<subscript>2</subscript>Ni<subscript>7</subscript>H<subscript>4.7</subscript> hydride
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Autor/in / Beteiligte Person: | Denys, R.V. ; Yartys, V.A. ; Sato, Masashi ; Riabov, A.B. ; Delaplane, R.G. |
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Zeitschrift: | Journal of Solid State Chemistry, Jg. 180 (2007-09-01), Heft 9, S. 2566-2576 |
Veröffentlichung: | 2007 |
Medientyp: | academicJournal |
ISSN: | 0022-4596 (print) |
DOI: | 10.1016/j.jssc.2007.07.002 |
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