Crystal structure of ytterbium trisilicide, YbSi3

Si 3 Yb,tetragonal, I4/mmm (no.139), a =7.1657(2)Å, c =10.6581(4)Å,V=547.3Å 3 , Z =8,R gt (F) =0.020, wR ref (F 2 ) =0.045, T =293 K. Source of materialYtterbium trisilicide was prepared by arc melting of the rare-earth metal (Hunan Metal Company, 99.9%,containing 270 ppm Ca and 180 ppm W) with silicon (Chempur, 99.999 %) followed by high-pressure high-temperature synthesis in aW alker-type module [1].Reacting mixtures with an atomic ratio of 1:3 at 9.5(9) GPa and 1320(130) Kusing typical reaction times between 60 and 240 minyielded polycrystalline powders of YbSi 3 .Single crystals were isolated from an ingot with astarting composition of 1:6 being compressed to 6.6(7) GPa and heated to 1770 Kfor 10 minbefore decreasing the temperature within 120 min to 1520 K at which the sample was kept for 60 min.Educt preparation, sample loading into and product isolation from the high-pressure equipment was performed in argon filled glove boxes (MBraun; H 2 O, O 2 <0.1 ppm).