A Quintupled Superstructure of the KHg₂ Type Realized for the New Stannide EuAuSn

Abstract

Abstract The title compound was prepared from the elements by reaction in a sealed tantalum tube at 1320 K followed by slow cooling to 970 K. EuAuSn crystallizes with a pronounced subcell of space group Imma (KHg 2 type). Additional very weak reflections required a quintupled b axis. The superstructure was refined from single‐crystal four‐circle diffractometer data ( Imm 2, a = 479.1(1) pm, b = 3833.6(5) pm, c = 820.1(1) pm, Z = 20, wR 2 = 0.0834, 3675 F 2 values and 94 variables). Six crystallographically different europium sites occur in the superstructure. Each europium site has an ordered near‐neighbour environment of six gold and six tin atoms in the form of two tilted hexagons. Magnetic susceptibility measurements show Curie‐Weiss behaviour above 50 K with an experimental magnetic moment of 7.6(1) μ B /Eu, indicating divalent europium. EuAuSn orders antiferromagnetically at about 12 K and undergoes a metamagnetic transition at a critical field of 2.0(2) T. Electrical conductivity measurements show metallic behaviour with a room temperature value of 260 μΩcm. 151 Eu and 119 Sn Mössbauer spectroscopic experiments are compatible with divalent europium and show complex magnetic hyperfine field splitting at low temperature.