The magnesium intermetallics <i>RE</i> ₂RuMg (<i>RE</i> = Sc, Y, Er, Tm, Lu) – i2 superstructures of the CuAu type

Abstract

Abstract The magnesium intermetallics RE 2 RuMg ( RE = Sc, Y, Er, Tm, Lu) were synthesized by melting of the elements in sealed niobium ampoules followed by different annealing sequences in muffle furnaces. The samples were characterized by powder X-ray diffraction. The structure of Sc 2 RuMg (Pt 2 ZnCd type, P 4/ mmm , a = 326.07(6), c = 760.9(2) pm, w R2 = 0.0749, 138 F 2 values, 9 variables) was refined from single crystal diffractometer data. Sc 2 RuMg is an i2 superstructure of the CuAu type with alternating and tetragonally distorted Ru@Sc 8 and Mg@Sc 8 cubes.