La2USe3S2: A Serendipitously Grown Lanthanide/Actinide Chalcogenide from a Eutectic Halide Flux
作者:Mohammad Usman、Gregory Morrison、Hans-Conrad zur Loye
DOI:10.1007/s10870-019-00780-x
日期:2019.9
La2USe3S2, exact composition La2USe2.96S2.04, crystallized from a reaction between USe2 and La2S3 in a molten CsCl/KCl eutectic flux and was characterized by single crystal X-ray diffraction. La2USe3S2 crystallizes in the orthorhombic space group Pnma in the U3S5 structure type with lattice parameters a = 12.3284(3) Å, b = 8.4028(2) Å, and c = 7.3452(2) Å. In La2USe3S2 all the anion sites have mixed S and Se occupancy and, henceforth, will be simply referred to as Q sites. The compound exhibits sigmoidal sheets built from LaQ8 (Q = S, Se) bicapped trigonal prisms that edge-share down the a-axis forming rectangular-shaped channels or tunnels. These tunnels are occupied by UQ6 (Q = S, Se) octahedra that edge-share to form infinite, one-dimensional chains running down the b-axis. X-ray diffraction quality single crystals of La2USe3S2 were grown from a molten CsCl/KCl eutectic flux at 950 °C and used for structure determination using single crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group Pnma in the U3S5 structure type.
La2USe3S2的精确组成是La2USe2.96S2.04,在熔融的CsCl/KCl共晶熔体中,USe2和La2S3发生反应结晶,并通过单晶X射线衍射进行了表征。La2USe3S2在正交晶系Pnma中以U3S5结构类型结晶,晶格参数为a=12.3284(3)Å、b=8.4028(2)Å、c=7.3452(2)Å。在La2US