SrPdGa3 – An orthorhombic superstructure of the ThCr2 Si2 type

Abstract

Abstract The gallide SrPdGa3 was synthesized by melting of the elements in a sealed tantalum tube in an induction furnace. SrPdGa3 crystallizes with a new structure type which was determined on the basis of single-crystal X-ray diffractometer data: Cmcm, a=643.7(1), b=1044.9(2), c=600.4(1) pm, wR=0.0283, 504 F 2 values, 19 variables. SrPdGa3 is a new ternary ordering variant of the aristotype BaAl4/ThCr2 Si2. The structural relation with ThCr2 Si2 and the closely related silicide BaNi2 Si2 is discussed on the basis of a group-subgroup relation. The three-dimensional [PdGa3]δ– network is dominated by Pd-Ga and Ga-Ga bonding interactions with 251–256 pm Pd-Ga and 267 pm Ga-Ga distances.