Barrelane-like germanium clusters in Eu{sub 3}Ge{sub 5}: Crystal structure, chemical bonding and physical properties

Journal Article · Tue Aug 15 00:00:00 EDT 2006 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.05.008· OSTI ID:20905381

Budnyk, Sergij ^[1]; Weitzer, Franz ^[2]; Kubata, Christof ^[3]; Collegium Helveticum, 3092 Zuerich ^[4]; Prots, Yurii ^[1]; Akselrud, Lev G ^[5]; Schnelle, Walter ^[1]; Hiebl, Kurt ^[2]; Nesper, Reinhard ^[3]; Collegium Helveticum, 3092 Zurich ^[4]; Wagner, Frank R ^[1]; Grin, Yuri ^[1]

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1. Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Str. 40, 01187 Dresden (Germany)
2. AG Neue Materialien, Universitaet Wien, Waehringerstr. 42, 1090 Vienna (Austria)
3. Laboratorium fuer Anorganische Chemie, ETH Hoenggerberg, HCI, 8093 Zurich (Switzerland)
4. Switzerland
5. Institut of Inorganic Chemistry, University of Lviv, Kyrylo and Methody Str. 6, 79005 Lviv (Ukraine)

Formation and crystal structure of the binary germanide Eu{sub 3}Ge{sub 5} were investigated in detail. The compound forms peritectically at 1008deg. C and does not undergo any phase transition down to room temperature. The crystal structure was determined first from X-ray powder diffraction data and was later confirmed by single-crystal X-ray diffraction: structure type Pu{sub 3}Pd{sub 5}, space group Cmcm (no. 63), a=9.7675(4)A, b=7.9681(3)A, c=9.8562(3)A. The main building blocks are Ge{sub 5}{sup 6-} cluster anions surrounded by Eu{sup 2+} cations. The nearly tetragonal-pyramidal shape is suggested by the interatomic distances. Contrary to that, the bonding analysis with the electron localization function (ELF) reveals only two- and three-bonded germanium atoms forming a strongly distorted [1.1.1]-barrelane-like cluster. Despite the formal electron deficiency, compared to the barrelane C{sub 5}H{sub 8}, the electron counting in the cluster anion and its conformation cannot be interpreted applying the Wade's rules. In accordance with the calculated electronic density of states, Eu{sub 3}Ge{sub 5} shows a metal-like temperature dependence of the electrical resistivity with a sharp change of {rho}(T) slope at the Neel point. Above the Neel point the inverse magnetic susceptibility reveals Curie-Weiss behavior with an effective moment of 8.11{mu}{sub B} (Eu{sup 2+}, 4f{sup 7} configuration) in agreement with the analysis of the chemical bonding. The 4f{sup 7} electronic configuration of europium is confirmed by Eu-L{sub III} X-ray absorption spectroscopy.

• OSTI ID: 20905381
• Journal Information: Journal of Solid State Chemistry, Vol. 179, Issue 8; Other Information: DOI: 10.1016/j.jssc.2006.05.008; PII: S0022-4596(06)00270-2; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
ANIONS
CHEMICAL BONDS
ELECTRIC CONDUCTIVITY
ELECTRONIC STRUCTURE
ELECTRONS
EUROPIUM COMPOUNDS
EUROPIUM IONS
GERMANIUM COMPOUNDS
MAGNETIC SUSCEPTIBILITY
MONOCRYSTALS
NEEL TEMPERATURE
ORTHORHOMBIC LATTICES
PHASE TRANSFORMATIONS
SPACE GROUPS
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY