TiNiSi-type YbIrMg with trivalent ytterbium

Abstract YbIrMg was obtained from a reaction of the elements in an equiatomic ratio in a sealed tantalum ampoule in a muffle furnace. The TiNiSi-type structure of YbIrMg was refined from single crystal X-ray diffractometer data: Pnma , a = 695.72(3), b = 405.84(6), c = 840.57(7) pm, wR = 0.0431, 511 F 2 values and 21 variables. A small degree of Mg/Ir mixing within the three-dimensional [IrMg] network leads to the refined composition YbIr 1.024(4) Mg 0.976(4) . The course of the cell volume in the RE IrMg series (Iandelli plot) points to trivalent ytterbium in YbIrMg.