Structure and physical properties of RE2Ge2In (RE = La, Ce, Pr, Nd)

The rare earth compounds RE2Ge2In (RE = La, Ce, Pr, Nd) were synthesized by arc-melting the elements under argon and investigated by X-ray diffraction on both powders and single crystals. The structures of the praseodymium and neodymium compounds have been refined on the basis of the single crystal data: Mo2FeB2 type, P4/mbm, a = 753.2(1) pm, c = 434.69(6) pm, wR2 = 0.0701, 272 F-2 values for Pr2Ge2In and a = 749.6(1) pm, c = 432.49(7) pm, wR2 = 0.0457, 317 F-2 values for Nd2Ge2In, with 12 variable parameters for each refinement. These structures can be considered as intergrowths of distorted AlB2 and CsCl related slabs of compositions REGe2 and REIn. respectively. The Ge-Ge distances within the AlB2 slabs are 253 pm for both Pr2Ge2In and Nd2Ge2In. Magnetic measurements have indicated that La2Ge2In is a diamagnet, whereas Ce2Ge2In, Pr2Ge2In and Nd2Ge2In exhibit localized magnetism of RE3+ ions with complex behavior at the lowest temperatures hinting at canted anti ferromagnetism or spin glass freezing. All four compounds studied show metallic electrical conductivity. (C) 2004 Elsevier SAS. All rights reserved.