X-Ray single-crystal investigation of rare earth osmium silicides

Abstract The crystal structure of the Nd 2 Os 3 Si 5 compound was refined from single-crystal X-ray diffraction ( P 4/ mnc space group, a =10.762(5) A, c =5.796(2) A) down to R =0.0662 for 393 reflections with F 0 >4σ( F 0 ). This compound belongs to a partly disordered U 2 Mn 3 Si 5 type structure: the Si2 site has been refined with a split position x , y , z (16 i ) instead of x , x +1/2,1/4 (8 g ), and for an occupancy of 50%. X-Ray single-crystal investigations of the PrOs 2 Si 2 and Ce(Ru 0.6 Os 0.4 ) 2 Si 2 compounds were also performed for the first time. Both compounds crystallize in the CeGa 2 Al 2 structure type, I 4/ mmm space group, with a =4.1678(4) A, c =9.901(1) A, R =0.0433 and a =4.173(1) A, c =9.797(3) A, R =0.0393, respectively.