Materials Data on U8NiS17 by Materials Project

Abstract

U8NiS17 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent U4+ sites. In the first U4+ site, U4+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of U–S bond distances ranging from 2.70–2.88 Å. In the second U4+ site, U4+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of U–S bond distances ranging from 2.71–2.79 Å. In the third U4+ site, U4+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of U–S bond distances ranging from 2.66–2.94 Å. Ni2+ is bonded in an octahedral geometry to six S2- atoms. There are two shorter (2.26 Å) and four longer (2.42 Å) Ni–S bond lengths. There are seven inequivalent S2- sites. In the first S2- site, S2- is bonded to four U4+ atoms to form distorted SU4 trigonal pyramids that share corners with two equivalent SU6 octahedra, corners with six equivalent SU3Ni tetrahedra, edges with two equivalent SU3Ni tetrahedra, and an edgeedge with one SU4 trigonal pyramid. The corner-sharing octahedral tilt angles are 38°. In the second S2- site, S2- is bonded to six U4+ atoms to form SU6 octahedra that share corners with four equivalent SU3Ni tetrahedra and corners with four equivalent SU4 trigonal pyramids. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to four U4+ atoms. In the fourth S2- site, S2- is bonded to three U4+ and one Ni2+ atom to form distorted SU3Ni tetrahedra that share a cornercorner with one SU6 octahedra, corners with five equivalent SU3Ni tetrahedra, corners with three equivalent SU4 trigonal pyramids, edges with two equivalent SU3Ni tetrahedra, and an edgeedge with one SU4 trigonal pyramid. The corner-sharing octahedral tilt angles are 53°. In the fifth S2- site, S2- is bonded in a rectangular see-saw-like geometry to four U4+ atoms. In the sixth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three U4+ and one Ni2+ atom. In the seventh S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four U4+ atoms.