Materials Data on Nb2Cr4Si5 by Materials Project
Nb2Cr4Si5 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. Nb2+ is bonded to seven Si+2.40- atoms to form a mixture of corner, edge, and face-sharing NbSi7 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.57–2.75 Å. There are two inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded in a 8-coordinate geometry to two equivalent Cr2+ and six Si+2.40- atoms. Both Cr–Cr bond lengths are 2.43 Å. There are a spread of Cr–Si bond distances ranging from 2.42–2.53 Å. In the second Cr2+ site, Cr2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of Cr–Si bond distances ranging from 2.35–2.74 Å. There are three inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to four equivalent Nb2+, four equivalent Cr2+, and two equivalent Si+2.40- atoms. Both Si–Si bond lengths are 2.43 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to one Nb2+, six Cr2+, and three equivalent Si+2.40- atoms. There are one shorter (2.35 Å) and two longer (2.69 Å) Si–Si bond lengths. In the third Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to four equivalent Nb2+ and five Cr2+ atoms.