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Z. Naturforsch. 2013, 68b, 971 – 978
doi:10.5560/ZNB.2013-3181
Ternary Antimonides RE4T7Sb6 (RE = Gd–Lu; T = Ru, Rh) with Cubic U4Re7Si6-type Structure
Inga Schellenberg, Ute Ch. Rodewald, Christian Schwickert, Matthias Eul, and Rainer Pöttgen
Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstrasse 30, 48149 Münster, Germany
Reprint requests to R. Pöttgen. E-mail: pottgen@uni-muenster.de
Received July 3, 2013 / published online September 4, 2013
The ternary antimonides RE4T7Sb6 (RE = Gd–Lu; T = Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Imm with a = 862.9(2) pm, wR2 = 0.0296, 163 F2 values for Er4Ru7Sb6; a = 864.1(1) pm, wR2 = 0.1423, 153 F2 values for Yb4Ru7Sb6; a = 872.0(2) pm, wR2 = 0.0427, 172 F2 values for Tb4Rh7Sb6; and a = 868.0(2) pm, wR2 = 0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE = Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion.
Key words: Antimonides, Crystal Structure, Magnetic Properties
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