Materials Data on Nb4Cr2Si5 by Materials Project
Nb4Cr2Si5 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. there are two inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to seven Si+2.40- atoms to form a mixture of distorted edge, face, and corner-sharing NbSi7 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.53–2.79 Å. In the second Nb2+ site, Nb2+ is bonded to seven Si+2.40- atoms to form a mixture of edge, face, and corner-sharing NbSi7 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.67–2.85 Å. Cr2+ is bonded in a 8-coordinate geometry to two equivalent Cr2+ and six Si+2.40- atoms. Both Cr–Cr bond lengths are 2.48 Å. There are a spread of Cr–Si bond distances ranging from 2.44–2.66 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 eight Nb2+ and two equivalent Si+2.40- atoms. Both Si–Si bond lengths are 2.48 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to five Nb2+, two equivalent Cr2+, and three equivalent Si+2.40- atoms. There are one shorter (2.64 Å) and two longer (2.80 Å) Si–Si bond lengths. In the third Si+2.40- site, Si+2.40- is bonded in a 11-coordinate geometry to five Nb2+, four equivalent Cr2+, and two equivalent Si+2.40- atoms. Both Si–Si bond lengths are 2.78 Å.