Crystal structures of five compounds in the aluminium-ruthenium-silicon system

Single crystals of five compounds with approximate compositions similar to Ru-16(Al0.78Si0.22)(47), (I), similar to Ru-9(Al0.70Si0.30)(32), (II), similar to Ru-10(Al0.67Si0.33)(41), (III), similar to Ru(Al0.57Si0.43)(5), (IV), and similar to Ru-2(Al0.46Si0.54)(9), (V), were obtained from polycrystalline lumps mainly composed of the target compounds, and their crystal structures were determined by means of single-crystal X-ray diffraction. The crystal structure of (I) can be related to that of a cubic rational crystalline approximant to an icosahedral quasicrystal through crystallographic shear and then unit-cell twinning. The crystal structure of (II) is isotypic with that of a phase with composition similar to Fe-9(Al,Si)(32). The crystal structure of (III) is comprised of edge-sharing Ru(Al,Si)(9-11) polyhedra with disordered chains along edges of polyhedra. The crystal structure of (IV) is of the LiIrSn4 type. The crystal structure of (V) can be viewed as a crystallographic shear structure derived from that of (IV).