Materials Data on Ni6SnSe2 by Materials Project
Ni6SnSe2 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. there are four 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, faces with four equivalent NiNi8Sn4 cuboctahedra, and faces with four equivalent SnNi12 cuboctahedra. There are four shorter (2.64 Å) and four longer (2.65 Å) Ni–Ni bond lengths. All Ni–Sn bond lengths are 2.61 Å. In the second Ni site, Ni is bonded in a distorted water-like geometry to two equivalent Ni, two equivalent Sn, and two equivalent Se atoms. Both Ni–Sn bond lengths are 2.64 Å. Both Ni–Se bond lengths are 2.43 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 Se atoms. Both Ni–Sn bond lengths are 2.66 Å. Both Ni–Se bond lengths are 2.33 Å. In the fourth Ni site, Ni is bonded in a 5-coordinate geometry to five Se atoms. There are one shorter (2.31 Å) and four longer (2.63 Å) Ni–Se bond lengths. Sn is bonded to twelve Ni atoms to form SnNi12 cuboctahedra that share corners with four equivalent SnNi12 cuboctahedra, faces with four equivalent NiNi8Sn4 cuboctahedra, and faces with four equivalent SnNi12 cuboctahedra. There are two inequivalent Se sites. In the first Se site, Se is bonded in a 8-coordinate geometry to eight Ni atoms. In the second Se site, Se is bonded in a 5-coordinate geometry to five Ni atoms.