Materials Data on USiS by Materials Project
USiS is Matlockite structured and crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. U6+ is bonded in a 5-coordinate geometry to four equivalent Si4- and five equivalent S2- atoms. All U–Si bond lengths are 3.02 Å. There are four shorter (2.70 Å) and one longer (2.81 Å) U–S bond lengths. Si4- is bonded to four equivalent U6+ and four equivalent Si4- atoms to form distorted SiU4Si4 hexagonal bipyramids that share corners with four equivalent SiU4Si4 hexagonal bipyramids, corners with twelve equivalent SU5 square pyramids, edges with four equivalent SiU4Si4 hexagonal bipyramids, edges with four equivalent SU5 square pyramids, and faces with four equivalent SiU4Si4 hexagonal bipyramids. All Si–Si bond lengths are 2.66 Å. S2- is bonded to five equivalent U6+ atoms to form distorted SU5 square pyramids that share corners with twelve equivalent SiU4Si4 hexagonal bipyramids, corners with four equivalent SU5 square pyramids, edges with four equivalent SiU4Si4 hexagonal bipyramids, and edges with eight equivalent SU5 square pyramids.