Materials Data on NbNiAs by Materials Project
NbNiAs crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Nb2+ is bonded to five equivalent As3- atoms to form distorted NbAs5 trigonal bipyramids that share corners with eight equivalent NiAs4 tetrahedra, corners with eight equivalent NbAs5 trigonal bipyramids, edges with six equivalent NiAs4 tetrahedra, and edges with six equivalent NbAs5 trigonal bipyramids. There are a spread of Nb–As bond distances ranging from 2.69–2.74 Å. Ni1+ is bonded to four equivalent As3- atoms to form NiAs4 tetrahedra that share corners with eight equivalent NiAs4 tetrahedra, corners with eight equivalent NbAs5 trigonal bipyramids, edges with two equivalent NiAs4 tetrahedra, and edges with six equivalent NbAs5 trigonal bipyramids. There are three shorter (2.38 Å) and one longer (2.40 Å) Ni–As bond lengths. As3- is bonded in a 9-coordinate geometry to five equivalent Nb2+ and four equivalent Ni1+ atoms.