TY - JOUR
T1 - Intermetallics as Zintl phases
T2 - Yb2Ga4Ge6 and RE3Ga4Ge6 (RE = Yb, Eu): Structural response of a [Ga4Ge6]4- framework to reduction by two electrons
AU - Zhuravleva, Marina A.
AU - Salvador, James
AU - Bilc, Daniel
AU - Mahanti, Subhendra D.
AU - Ireland, John
AU - Kannewurf, Carl R.
AU - Kanatzidis, Mercouri G.
PY - 2004/7/5
Y1 - 2004/7/5
N2 - Two new intermetallic compounds, Yb2Ga4Ge6 and Yb3Ga4Ge6, were obtained from reactions in molten Ga. A third compound, Eu3Ga4Ge6, was produced by direct combination of the elements. The crystal structures of these compounds were studied by single-crystal X-ray diffraction. Yb 2Ga4Ge6 crystallizes in an orthorhombic cell with a=4.1698(7), b= 23.254(4), c=10.7299(18) A in the polar space group Cmc21. The structure of RE3Ga4Ge6 is monoclinic, space group C2/m, with cell parameters a= 23.941(6), b=4.1928(11), C= 10.918(3) Å, β=91.426(4)° for RE=Yb, and a=24.136(2), b=4.3118(4), c=11.017(1) Å, β=91.683(2)° for RE=Eu. The refinement [I>2σ(I)] converged to the final residuals R 1/wR2=0.0229/0.0589, 0.0411/0.1114, and 0.0342/0.0786 for Yb2Ga4Ge6, Yb3Ga4Ge 6, and Eu3Ga4Ge6, respectively. The structures of these two families of compounds can be described by a Zintl concept of bonding, in which the three-dimensional [Ga4Ge 6]n- framework serves as a host and electron sink for the electropositive RE atoms. The structural relation of RE3Ga 4Ge6 to of Yb2Ga4Ge6 lies in a monoclinic distortion of the orthorhombic cell of Yb2Ga 4Ge6 and reduction of the [Ga4Ge6] network by two electrons per formula unit. The results of theoretical calculations of the electronic structure, electrical transport data, and thermochemical and magnetic measurements are also reported.
AB - Two new intermetallic compounds, Yb2Ga4Ge6 and Yb3Ga4Ge6, were obtained from reactions in molten Ga. A third compound, Eu3Ga4Ge6, was produced by direct combination of the elements. The crystal structures of these compounds were studied by single-crystal X-ray diffraction. Yb 2Ga4Ge6 crystallizes in an orthorhombic cell with a=4.1698(7), b= 23.254(4), c=10.7299(18) A in the polar space group Cmc21. The structure of RE3Ga4Ge6 is monoclinic, space group C2/m, with cell parameters a= 23.941(6), b=4.1928(11), C= 10.918(3) Å, β=91.426(4)° for RE=Yb, and a=24.136(2), b=4.3118(4), c=11.017(1) Å, β=91.683(2)° for RE=Eu. The refinement [I>2σ(I)] converged to the final residuals R 1/wR2=0.0229/0.0589, 0.0411/0.1114, and 0.0342/0.0786 for Yb2Ga4Ge6, Yb3Ga4Ge 6, and Eu3Ga4Ge6, respectively. The structures of these two families of compounds can be described by a Zintl concept of bonding, in which the three-dimensional [Ga4Ge 6]n- framework serves as a host and electron sink for the electropositive RE atoms. The structural relation of RE3Ga 4Ge6 to of Yb2Ga4Ge6 lies in a monoclinic distortion of the orthorhombic cell of Yb2Ga 4Ge6 and reduction of the [Ga4Ge6] network by two electrons per formula unit. The results of theoretical calculations of the electronic structure, electrical transport data, and thermochemical and magnetic measurements are also reported.
KW - Flux synthesis
KW - Gallium
KW - Germanium
KW - Lanthanides
KW - Zintl phases
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U2 - 10.1002/chem.200305755
DO - 10.1002/chem.200305755
M3 - Article
C2 - 15224328
AN - SCOPUS:3142662688
SN - 0947-6539
VL - 10
SP - 3197
EP - 3208
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 13
ER -