Materials Data on Ni5As2 by Materials Project
Ni5As2 crystallizes in the hexagonal P6_3cm space group. The structure is three-dimensional. there are six inequivalent Ni+1.20+ sites. In the first Ni+1.20+ site, Ni+1.20+ is bonded to four As3- atoms to form NiAs4 tetrahedra that share corners with three equivalent NiAs5 square pyramids, corners with twelve NiAs4 tetrahedra, edges with three equivalent NiAs5 square pyramids, and edges with three equivalent NiAs4 tetrahedra. There are three shorter (2.43 Å) and one longer (2.45 Å) Ni–As bond lengths. In the second Ni+1.20+ site, Ni+1.20+ is bonded to four As3- atoms to form NiAs4 tetrahedra that share corners with six equivalent NiAs5 square pyramids, corners with twelve NiAs4 tetrahedra, edges with three equivalent NiAs5 square pyramids, and edges with three equivalent NiAs4 tetrahedra. There are three shorter (2.45 Å) and one longer (2.52 Å) Ni–As bond lengths. In the third Ni+1.20+ site, Ni+1.20+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. All Ni–As bond lengths are 2.38 Å. In the fourth Ni+1.20+ site, Ni+1.20+ is bonded to four As3- atoms to form distorted NiAs4 tetrahedra that share corners with seven equivalent NiAs5 square pyramids, corners with twelve NiAs4 tetrahedra, an edgeedge with one NiAs5 square pyramid, and edges with five NiAs4 tetrahedra. There are a spread of Ni–As bond distances ranging from 2.35–2.60 Å. In the fifth Ni+1.20+ site, Ni+1.20+ is bonded to four As3- atoms to form NiAs4 tetrahedra that share corners with two equivalent NiAs5 square pyramids, corners with fourteen NiAs4 tetrahedra, edges with two equivalent NiAs5 square pyramids, edges with four NiAs4 tetrahedra, and a faceface with one NiAs5 square pyramid. There are a spread of Ni–As bond distances ranging from 2.31–2.44 Å. In the sixth Ni+1.20+ site, Ni+1.20+ is bonded to five As3- atoms to form distorted NiAs5 square pyramids that share corners with two equivalent NiAs5 square pyramids, corners with fourteen NiAs4 tetrahedra, edges with four equivalent NiAs5 square pyramids, edges with six NiAs4 tetrahedra, and a faceface with one NiAs4 tetrahedra. There are a spread of Ni–As bond distances ranging from 2.31–2.74 Å. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 10-coordinate geometry to ten Ni+1.20+ atoms. In the second As3- site, As3- is bonded in a 10-coordinate geometry to ten Ni+1.20+ atoms. In the third As3- site, As3- is bonded in a 10-coordinate geometry to ten Ni+1.20+ atoms.