The Indium‐Rich Intermetallics YbCoIn5, YbRhIn5, and YbPtIn4

Abstract

AbstractThe indium‐rich intermetallic compounds YbCoIn5 and YbRhIn5 were prepared from the elements in sealed tantalum tubes by the indium flux technique with a starting composition 1:1:7. The tubes were heated at 1320 K (YbCoIn5) and 1300 K (YbRhIn5) for six hours followed by slow cooling (5 K/h) to 670 K. YbPtIn4 was prepared in a sealed molybdenum crucible from an arc‐melted precursor alloy YbPtIn2 with additional indium (6 h at 1370 K followed by slow cooling at a rate of 5 K/h). The structures of the three indides were investigated by single crystal X‐ray data: P4/mmm, HoCoGa5 type, a = 455.90(7), c = 743.3(1) pm, wR2 = 0.0487, 173 F2 values for YbCoIn5, a = 459.52(6), c = 744.2(2) pm, wR2 = 0.0803, 238 F2 values for YbRhIn5 with 12 variables per refinement, and Cmcm, YNiAl4 type, a = 444.5(1), b = 1655.0(1), c = 751.6(1) pm, wR2 = 0.1036, 482 F2 values, 24 variables for YbPtIn4. The transition metal atoms in YbCoIn5 and YbRhIn5 have eight indium neighbors in a square prismatic coordination by indium atoms. These prisms are condensed via common edges forming layers. The ytterbium and further indium atoms are located between these layers. The ytterbium atoms are cuboctahedrally coordinated by twelve indium atoms. The cell volumes indicate intermediate‐valent or divalent ytterbium for YbCoIn5 and YbRhIn5. The YbPtIn4 structure consists of a three‐dimensional [PtIn4] network in which the ytterbium atoms are located in distorted hexagonal channels. Common structural motifs of the three structures are distorted bcc‐like indium cubes which resemble the structure of elemental indium.