DOE OSTI2020
U2SeS is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are two inequivalent U sites. In the first U site, U is bonded to four equivalent Se and two equivalent S atoms to form a mixture of corner and edge-sharing USe4S2 octahedra. The corner-sharing octahedral tilt angles are 0°. All U–Se bond lengths are 2.80 Å. Both U–S bond lengths are 2.80 Å. In the second U site, U is bonded to two equivalent Se and four equivalent S atoms to form USe2S4 octahedra that share corners with six equivalent USe2S4 octahedra and edges with twelve USe4S2 octahedra. The corner-sharing octahedral tilt angles are 0°. Both U–Se bond lengths are 2.80 Å. All U–S bond lengths are 2.80 Å. Se is bonded to six U atoms to form SeU6 octahedra that share corners with six equivalent SeU6 octahedra, edges with four equivalent SeU6 octahedra, and edges with eight equivalent SU6 octahedra. The corner-sharing octahedral tilt angles are 0°. S is bonded to six U atoms to form SU6 octahedra that share corners with six equivalent SU6 octahedra, edges with four equivalent SU6 octahedra, and edges with eight equivalent SeU6 octahedra. The corner-sharing octahedral tilt angles are 0°.