Materials Data on Si6NiMo9 by Materials Project

Abstract

Mo9NiSi6 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. there are two inequivalent Mo+2.44+ sites. In the first Mo+2.44+ site, Mo+2.44+ is bonded to six Si4- atoms to form distorted MoSi6 pentagonal pyramids that share corners with fifteen equivalent MoSi6 pentagonal pyramids, corners with two equivalent MoSi4 tetrahedra, corners with two equivalent NiSi4 tetrahedra, edges with three equivalent MoSi6 pentagonal pyramids, an edgeedge with one MoSi4 tetrahedra, an edgeedge with one NiSi4 tetrahedra, and faces with seven equivalent MoSi6 pentagonal pyramids. There are a spread of Mo–Si bond distances ranging from 2.54–2.90 Å. In the second Mo+2.44+ site, Mo+2.44+ is bonded to four equivalent Si4- atoms to form MoSi4 tetrahedra that share corners with sixteen equivalent MoSi6 pentagonal pyramids, edges with eight equivalent MoSi6 pentagonal pyramids, and edges with two equivalent NiSi4 tetrahedra. All Mo–Si bond lengths are 2.56 Å. Ni2+ is bonded to four equivalent Si4- atoms to form distorted NiSi4 tetrahedra that share corners with sixteen equivalent MoSi6 pentagonal pyramids, edges with eight equivalent MoSi6 pentagonal pyramids, and edges with two equivalent MoSi4 tetrahedra. All Ni–Si bond lengths are 2.45 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 10-coordinate geometry to nine Mo+2.44+ and one Ni2+ atom. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to eight equivalent Mo+2.44+ and two equivalent Si4- atoms. Both Si–Si bond lengths are 2.47 Å.