Materials Data on Nb4Co3Si7 by Materials Project
Nb4Co3Si7 crystallizes in the orthorhombic F222 space group. The structure is three-dimensional. there are three inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to seven Si+1.71- atoms to form distorted NbSi7 pentagonal bipyramids that share corners with eight NbSi7 pentagonal bipyramids, edges with three equivalent NbSi7 pentagonal bipyramids, and faces with six NbSi9 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.54–2.85 Å. In the second Nb2+ site, Nb2+ is bonded to nine Si+1.71- atoms to form distorted NbSi9 pentagonal bipyramids that share corners with six NbSi7 pentagonal bipyramids, edges with three NbSi9 pentagonal bipyramids, and faces with eight NbSi7 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.67–3.04 Å. In the third Nb2+ site, Nb2+ is bonded to seven Si+1.71- atoms to form distorted NbSi7 pentagonal bipyramids that share corners with eight NbSi7 pentagonal bipyramids, edges with two NbSi9 pentagonal bipyramids, and faces with six NbSi7 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.60–2.90 Å. There are three inequivalent Co+1.33+ sites. In the first Co+1.33+ site, Co+1.33+ is bonded in a 6-coordinate geometry to six Si+1.71- atoms. There are a spread of Co–Si bond distances ranging from 2.31–2.73 Å. In the second Co+1.33+ site, Co+1.33+ is bonded in a 4-coordinate geometry to six Si+1.71- atoms. There are a spread of Co–Si bond distances ranging from 2.23–2.85 Å. In the third Co+1.33+ site, Co+1.33+ is bonded in a 6-coordinate geometry to eight Si+1.71- atoms. There are a spread of Co–Si bond distances ranging from 2.29–2.98 Å. There are six inequivalent Si+1.71- sites. In the first Si+1.71- site, Si+1.71- is bonded in a 10-coordinate geometry to eight Nb2+ and two equivalent Si+1.71- atoms. There are one shorter (2.44 Å) and one longer (2.51 Å) Si–Si bond lengths. In the second Si+1.71- site, Si+1.71- is bonded in a 12-coordinate geometry to four Nb2+, two equivalent Co+1.33+, and six Si+1.71- atoms. There are a spread of Si–Si bond distances ranging from 2.39–2.88 Å. In the third Si+1.71- site, Si+1.71- is bonded in a 12-coordinate geometry to six Co+1.33+ and six Si+1.71- atoms. There are a spread of Si–Si bond distances ranging from 2.35–2.60 Å. In the fourth Si+1.71- site, Si+1.71- is bonded in a 11-coordinate geometry to five Nb2+ and four Co+1.33+ atoms. In the fifth Si+1.71- site, Si+1.71- is bonded in a 9-coordinate geometry to five Nb2+, two equivalent Co+1.33+, and two equivalent Si+1.71- atoms. In the sixth Si+1.71- site, Si+1.71- is bonded in a 9-coordinate geometry to four Nb2+, three Co+1.33+, and two Si+1.71- atoms.