Deuterium ordering in Laves-phase deuteride YFe{sub 2}D{sub 4.2}

Journal Article · Wed Jul 15 00:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.04.033· OSTI ID:21370501

Ropka, J ^[1]; Cerny, R ^[1]; Paul-Boncour, V ^[2]; Proffen, Th ^[3]

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1. Laboratory of Crystallography, University of Geneva, quai E.-Ansermet 24, CH-1211 Geneva (Switzerland)
2. CMTR, ICMPE, CNRS, 2 rue H. Dunant, 94320 Thiais Cedex (France)
3. Lujan Neutron Scattering Center, LANL, MS H805, Los Alamos, NM 87545 (United States)

The structure of Laves-phase deuteride YFe{sub 2}D{sub 4.2} has been investigated by synchrotron and neutron (ToF) powder diffraction experiments between 60 and 370 K. Below 323 K, YFe{sub 2}D{sub 4.2} crystallizes in a fully ordered, monoclinic structure (s.g. Pc, Z=8, a=5.50663(4), b=11.4823(1), c=9.42919(6) A, beta=122.3314(5){sup o}, V=503.765(3) A{sup 3} at 290 K) containing 4 yttrium, 8 iron and 18 deuterium atoms. Most D-D distances are, within the precision of the diffraction experiment, longer than 2.1 A; the shortest ones are of 1.96 A. Seven of eight iron atoms are coordinated by deuterium in a trigonal bipyramid, similar to that in TiFeD{sub 1.95-2}. The eighth iron atom is coordinated by deuterium in a tetrahedral configuration. The coordination of iron by deuterium, and the iron-deuterium distances point to the importance of the directional bonding between iron and deuterium atoms. The lowering of crystal symmetry due to deuterium ordering occurs at much higher temperature than the magnetic ordering, and is therefore one of the parameters that are at the origin of the magnetic transition at lower temperatures. - Graphical abstract: Laves-phase deuteride YFe{sub 2}D{sub 4.2} crystallizes below 323 K in fully ordered monoclinic structure. Seven iron atoms from eight are coordinated by deuterium in a trigonal bipyramid, similar to that in TiFeD{sub 1.95-2}. The eights iron atom is coordinated by deuterium in a tetrahedral configuration.

• OSTI ID: 21370501
• Journal Information: Journal of Solid State Chemistry, Vol. 182, Issue 7; Other Information: DOI: 10.1016/j.jssc.2009.04.033; PII: S0022-4596(09)00192-3; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTALS
DEUTERIDES
DEUTERIUM
IRON COMPOUNDS
LAVES PHASES
MAGNETIZATION
MONOCLINIC LATTICES
NEUTRON DIFFRACTION
TEMPERATURE RANGE 0273-0400 K
YTTRIUM COMPOUNDS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DEUTERIUM COMPOUNDS
DIFFRACTION
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
SCATTERING
STABLE ISOTOPES
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS