Materials Data on Ba6Ni25S27 by Materials Project
Ba6Ni25S27 crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine S2- atoms. There are a spread of Ba–S bond distances ranging from 3.07–3.29 Å. There are two inequivalent Ni+1.68+ sites. In the first Ni+1.68+ site, Ni+1.68+ is bonded to four S2- atoms to form NiS4 tetrahedra that share a cornercorner with one NiS6 octahedra, corners with five equivalent NiS4 tetrahedra, and edges with three equivalent NiS4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. There are three shorter (2.21 Å) and one longer (2.25 Å) Ni–S bond lengths. In the second Ni+1.68+ site, Ni+1.68+ is bonded to six equivalent S2- atoms to form corner-sharing NiS6 octahedra. All Ni–S bond lengths are 2.40 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Ba2+ and three equivalent Ni+1.68+ atoms to form distorted SBa3Ni3 octahedra that share corners with three equivalent SBa3Ni3 octahedra, edges with three equivalent SBa3Ni3 octahedra, and a faceface with one SBa6 octahedra. The corner-sharing octahedral tilt angles are 29°. In the second S2- site, S2- is bonded in a 5-coordinate geometry to five Ni+1.68+ atoms. In the third S2- site, S2- is bonded to six equivalent Ba2+ atoms to form face-sharing SBa6 octahedra. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent Ba2+ and four equivalent Ni+1.68+ atoms.