DOE OSTI2020
Ni9(SnS)2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. there are five inequivalent Ni sites. In the first Ni site, Ni is bonded to eight Ni and four equivalent Sn atoms to form NiNi8Sn4 cuboctahedra that share corners with four equivalent NiNi8Sn4 cuboctahedra, edges with eight equivalent NiNi8Sn4 cuboctahedra, edges with eight equivalent SnNi12 cuboctahedra, faces with four equivalent SnNi12 cuboctahedra, and faces with twelve NiNi8Sn4 cuboctahedra. There are four shorter (2.60 Å) and four longer (2.62 Å) Ni–Ni bond lengths. All Ni–Sn bond lengths are 2.64 Å. In the second Ni site, Ni is bonded to eight Ni and four equivalent Sn atoms to form NiNi8Sn4 cuboctahedra that share corners with eight equivalent NiNi8Sn4 cuboctahedra, edges with four equivalent SnNi12 cuboctahedra, edges with eight equivalent NiNi8Sn4 cuboctahedra, faces with four equivalent SnNi12 cuboctahedra, and faces with nine NiNi8Sn4 cuboctahedra. There are two shorter (2.68 Å) and two longer (2.70 Å) Ni–Ni bond lengths. All Ni–Sn bond lengths are 2.63 Å. In the third Ni site, Ni is bonded in a distorted water-like geometry to two equivalent Ni, two equivalent Sn, and two equivalent S atoms. Both Ni–Sn bond lengths are 2.63 Å. Both Ni–S bond lengths are 2.25 Å. In the fourth Ni site, Ni is bonded in a distorted bent 120 degrees geometry to two equivalent Ni, two equivalent Sn, and two equivalent S atoms. Both Ni–Sn bond lengths are 2.66 Å. Both Ni–S bond lengths are 2.23 Å. In the fifth Ni site, Ni is bonded to four equivalent S atoms to form corner-sharing NiS4 tetrahedra. All Ni–S bond lengths are 2.25 Å. Sn is bonded to twelve Ni atoms to form SnNi12 cuboctahedra that share corners with eight equivalent SnNi12 cuboctahedra, edges with twelve NiNi8Sn4 cuboctahedra, faces with five equivalent SnNi12 cuboctahedra, and faces with eight NiNi8Sn4 cuboctahedra. S is bonded in a distorted hexagonal planar geometry to six Ni atoms.