Cu7Si2 crystallizes in the trigonal P-3m1 space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 11-coordinate geometry to one Cu(2), three equivalent Cu(3), three equivalent Cu(4), and four equivalent Si(1) atoms. In the second Cu site, Cu(2) is bonded in a 11-coordinate geometry to one Cu(1), three equivalent Cu(2), six equivalent Cu(3), and one Si(1) atom. In the third Cu site, Cu(3) is bonded in a 14-coordinate geometry to one Cu(3), one Cu(4), three equivalent Cu(1), six equivalent Cu(2), and three equivalent Si(1) atoms. In the fourth Cu site, Cu(4) is bonded in a 14-coordinate geometry to two equivalent Cu(3), six equivalent Cu(1), and six equivalent Si(1) atoms. Si(1) is bonded in a 11-coordinate geometry to one Cu(2), three equivalent Cu(3), three equivalent Cu(4), and four equivalent Cu(1) atoms.
Cu7Si2 crystallizes in the trigonal P-3m1 space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 11-coordinate geometry to one Cu(2), three equivalent Cu(3), three equivalent Cu(4), and four equivalent Si(1) atoms. The Cu(1)-Cu(2) bond length is 2.59 Å. All Cu(1)-Cu(3) bond lengths are 2.71 Å. All Cu(1)-Cu(4) bond lengths are 2.63 Å. There are three shorter (2.37 Å) and one longer (2.63 Å) Cu(1)-Si(1) bond length. In the second Cu site, Cu(2) is bonded in a 11-coordinate geometry to one Cu(1), three equivalent Cu(2), six equivalent Cu(3), and one Si(1) atom. All Cu(2)-Cu(2) bond lengths are 2.36 Å. There are three shorter (2.67 Å) and three longer (2.70 Å) Cu(2)-Cu(3) bond lengths. The Cu(2)-Si(1) bond length is 2.37 Å. In the third Cu site, Cu(3) is bonded in a 14-coordinate geometry to one Cu(3), one Cu(4), three equivalent Cu(1), six equivalent Cu(2), and three equivalent Si(1) atoms. The Cu(3)-Cu(3) bond length is 2.57 Å. The Cu(3)-Cu(4) bond length is 2.51 Å. All Cu(3)-Si(1) bond lengths are 2.58 Å. In the fourth Cu site, Cu(4) is bonded in a 14-coordinate geometry to two equivalent Cu(3), six equivalent Cu(1), and six equivalent Si(1) atoms. All Cu(4)-Si(1) bond lengths are 2.77 Å. Si(1) is bonded in a 11-coordinate geometry to one Cu(2), three equivalent Cu(3), three equivalent Cu(4), and four equivalent Cu(1) atoms.