Synthesis, structure and properties of SrAu3In3 and EuAu3In3 - New indides with gold zig-zag chains

摘要

New indides SrAu3In3 and EuAu3In3 were synthesized by induction melting of the elements in sealed tantalum tubes. Both indides were characterized by X-ray diffraction on powders and single crystals. They crystallize with a new orthorhombic structure type: Pmmn, Z=2, a = 455.26(9), b = 775.9(2), c = 904.9(2) pm, wR2 = 0.0425, 485 F-2 values for SrAu3In3 and a = 454.2(2), b = 768.1(6), c=907.3(6) pm, wR2 = 0.0495, 551 F-2 values for EuAu3In3 with 26 variables for each refinement. The gold and indium atoms build up three-dimensional [Au3In3] polyanionic networks, which leave distorted hexagonal channels for the strontium and europium atoms. Within the networks one observes Au2 atoms without Au-Au contacts and gold zig-zag chains (279pm Aul-Aul in EuAu3In3). The Au-In and In-In distances in EuAu3In3 range from 270 to 290 and from 305 to 355pm. The europium atoms within the distorted hexagonal channels have coordination number 14 (8 Au + 6 In). EuAu3In3 shows Curie-Weiss behavior above 50 K with an experimental magnetic moment of 8.1(1) mu B/Eu atom. Eu-151 Mossbauer spectra show a single signal at delta=-11.31(1) mm/s, compatible with divalent europium. No magnetic ordering was detected down to 3 K. (C) 2007 Elsevier Inc. All rights reserved.