SrRhIn2, SrPdIn2, Srlrln2, and SrPtIn2 - New Intermetallic Compounds with a Filled Variant of the Caln2 Structure

Z. Naturforsch. 54 b, 38-44 (1999); received August 28, 1998 Intermetallic Compounds, Crystal Structure, Chemical Bonding SrRhlm, SrPdIn2, Srlrln2, and SrPtIn2 have been synthesized by reaction of mixtures of the elements in glassy carbon crucibles in a high-frequency furnace. The new compounds were investigated by X-ray diffraction on powders as well as single crystals; a = 437.3(2), b = 1091.9(5), c = 798.0(2) pm for SrRhln^, a = 453.54(7), b = 1079.8(2), c = 790.4(1) pm for SrPdIn2, a = 434.83(8),b= 1102.6(2) ,c = 798.6(2) pm for Srlrln2, a = 447.5( 1) ,b = 1091.0(3), c = 787.6( 1) pm for SrPtIn2. They adopt the MgCuAl2 structure, a ternary ordered version of Re^B. Chemical bonding analysis leads to the description of a filled Srln2 structure in which the In-in-bonding is modified by the insertion of transition metal atoms into the planar strontium layers, thus favoring strong indium-transition metal