Materials Data on Nb7As4 by Materials Project
Nb7As4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are eight inequivalent Nb sites. In the first Nb site, Nb is bonded in a square co-planar geometry to four As atoms. There are two shorter (2.60 Å) and two longer (2.75 Å) Nb–As bond lengths. In the second Nb site, Nb is bonded in a distorted square co-planar geometry to four As atoms. There are two shorter (2.68 Å) and two longer (2.74 Å) Nb–As bond lengths. In the third Nb site, Nb is bonded in a 4-coordinate geometry to five As atoms. There are a spread of Nb–As bond distances ranging from 2.68–3.09 Å. In the fourth Nb site, Nb is bonded in a 4-coordinate geometry to four As atoms. There are a spread of Nb–As bond distances ranging from 2.57–2.78 Å. In the fifth Nb site, Nb is bonded to five As atoms to form a mixture of distorted face, edge, and corner-sharing NbAs5 trigonal bipyramids. There are a spread of Nb–As bond distances ranging from 2.56–2.69 Å. In the sixth Nb site, Nb is bonded in a 5-coordinate geometry to five As atoms. There are a spread of Nb–As bond distances ranging from 2.65–3.06 Å. In the seventh Nb site, Nb is bonded to five As atoms to form a mixture of distorted face, edge, and corner-sharing NbAs5 trigonal bipyramids. There are a spread of Nb–As bond distances ranging from 2.59–2.66 Å. In the eighth Nb site, Nb is bonded in a 5-coordinate geometry to five As atoms. There are a spread of Nb–As bond distances ranging from 2.68–2.96 Å. There are four inequivalent As sites. In the first As site, As is bonded in a 8-coordinate geometry to eight Nb atoms. In the second As site, As is bonded to seven Nb atoms to form a mixture of distorted edge and corner-sharing AsNb7 pentagonal bipyramids. In the third As site, As is bonded in a 9-coordinate geometry to nine Nb atoms. In the fourth As site, As is bonded in a 9-coordinate geometry to nine Nb atoms.