NaCu4Sb2 crystallizes in the trigonal R-3m space group. Na(1) is bonded to six equivalent Sb(1) atoms to form distorted edge-sharing NaSb6 octahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 10-coordinate geometry to three equivalent Cu(1), three equivalent Cu(2), and four equivalent Sb(1) atoms. In the second Cu site, Cu(2) is bonded in a 7-coordinate geometry to one Cu(2), three equivalent Cu(1), and three equivalent Sb(1) atoms. Sb(1) is bonded in a 10-coordinate geometry to three equivalent Na(1), three equivalent Cu(2), and four equivalent Cu(1) atoms.
NaCu4Sb2 crystallizes in the trigonal R-3m space group. Na(1) is bonded to six equivalent Sb(1) atoms to form distorted edge-sharing NaSb6 octahedra. All Na(1)-Sb(1) bond lengths are 3.25 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 10-coordinate geometry to three equivalent Cu(1), three equivalent Cu(2), and four equivalent Sb(1) atoms. All Cu(1)-Cu(1) bond lengths are 2.72 Å. All Cu(1)-Cu(2) bond lengths are 2.54 Å. There is one shorter (2.67 Å) and three longer (2.86 Å) Cu(1)-Sb(1) bond lengths. In the second Cu site, Cu(2) is bonded in a 7-coordinate geometry to one Cu(2), three equivalent Cu(1), and three equivalent Sb(1) atoms. The Cu(2)-Cu(2) bond length is 2.52 Å. All Cu(2)-Sb(1) bond lengths are 2.58 Å. Sb(1) is bonded in a 10-coordinate geometry to three equivalent Na(1), three equivalent Cu(2), and four equivalent Cu(1) atoms.