Low- and high-temperature structures of YbCuBi

Abstract A variable temperature single-crystal X-ray diffraction study was undertaken on the intermetallic compound YbCuBi, which undergoes a phase transition at ∼375 K. At low temperatures ( T = 193 K, a = 4.5821(3) Å, c = 7.8107(8) Å; T = 295 K, a = 4.5825(6) Å, c = 7.8597(10) Å), YbCuBi adopts the LiGaGe-type (ordered CaIn 2 -type) structure (Pearson symbol hP 6, space group P 6 3 mc , Z = 2). At high temperatures ( T = 393 K, a = 4.5885(14) Å, c = 7.913(2) Å; T = 473 K, a = 4.594(4) Å, c = 7.928(6) Å), YbCuBi adopts the ZrBeSi-type (ordered Ni 2 In-type) structure (Pearson symbol hP 6, space group P 6 3 / mmc , Z = 2). The structure consists of Yb atoms separating hexagonal ∞ 2 [CuBi] nets, which are buckled at low temperatures but planar at high temperatures.