Materials Data on Cu7Si2 by Materials Project
Cu7Si2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are four inequivalent Cu+1.14+ sites. In the first Cu+1.14+ site, Cu+1.14+ is bonded in a 4-coordinate geometry to four equivalent Si4- atoms. There are three shorter (2.37 Å) and one longer (2.63 Å) Cu–Si bond lengths. In the second Cu+1.14+ site, Cu+1.14+ is bonded to three equivalent Cu+1.14+ and one Si4- atom to form corner-sharing CuCu3Si trigonal pyramids. All Cu–Cu bond lengths are 2.36 Å. The Cu–Si bond length is 2.37 Å. In the third Cu+1.14+ site, Cu+1.14+ is bonded in a 4-coordinate geometry to two Cu+1.14+ and three equivalent Si4- atoms. There are one shorter (2.51 Å) and one longer (2.57 Å) Cu–Cu bond lengths. All Cu–Si bond lengths are 2.58 Å. In the fourth Cu+1.14+ site, Cu+1.14+ is bonded in a 8-coordinate geometry to two equivalent Cu+1.14+ and six equivalent Si4- atoms. All Cu–Si bond lengths are 2.77 Å. Si4- is bonded in a 11-coordinate geometry to eleven Cu+1.14+ atoms.