%0 Journal Article
%A Sichevych, O.
%A Kohout, M.
%A Schnelle, W.
%A Borrmann, H.
%A Cardoso-Gil, R.
%A Schmidt, M.
%A Burkhardt, U.
%A Grin, Yu.
%A DESY
%T EuTM<sub>2</sub>Ga<sub>8</sub> (TM= Co, Rh, Ir) - A Contribution to the Chemistry of the CeFe<sub>2</sub>Al<sub>8</sub> -type Compounds
%J Inorganic chemistry
%V 48
%@ 0020-1669
%C Washington, DC
%I American Chemical Society
%M PHPPUBDB-12122
%P 6261 - 6270
%D 2009
%Z (c) American Chemical Society; Post referee fulltext in progress 2; Embargo 12 months from publication
%X The isostructural compounds EuTM(2)Ga(8) (TM = Co, Rh, Ir) were prepared by direct reaction of the elements by high-frequency thermal treatment. All three phases are isotypic with CeFe(2)Al(8) (space group Pbam, Pearson symbol oP44, Z = 4). The crystal structure was established from single-crystal X-ray diffraction data: a = 12.4322(7) A, b = 14.3814(9) A, and c = 4.0378(2) A for EuCo(2)Ga(8); a = 12.6001(6) A, b = 14.6757(7) A, and c = 4.1172(2) A for EuRh(2)Ga(8); and a = 12.6237(7) A, b = 14.6978(8) A, and c = 4.1486(2) A for EuIr(2)Ga(8), respectively. Analysis of the chemical bonding in EuRh(2)Ga(8) with the electron localizability tools reveals formation of the 3D [Rh(2)Ga(8)] polyanion build by polar covalent bonds. Europium interacts in two ways with the polyanion: mainly as a cation by charge transfer and additionally covalently by means of the electrons of the inner shells. Magnetic susceptibility measurements show Curie-Weiss paramagnetic behavior above 40 K with effective magnetic moments of 7.81, 8.05, and 8.27 micro(B)/f.u. for EuTM(2)Ga(8) (TM = Co, Rh, Ir). Antiferromagnetic ordering of Eu moments is observed in all three compounds below 20 K. Independently on the chemical composition of the coordination sphere, magnetic behavior and, especially, X-ray absorption spectra indicate predominantly the 4f(7) electronic configuration of europium with small admixture of the 4f(6) state.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:19469500
%U <Go to ISI:>//WOS:000267507400080
%R 10.1021/ic900573w
%U https://bib-pubdb1.desy.de/record/93384