Cu5Sn4 crystallizes in the monoclinic C2 space group. There are eight inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 11-coordinate geometry to two equivalent Cu(3), two equivalent Cu(6), two equivalent Cu(7), one Sn(1), two equivalent Sn(4), and two equivalent Sn(6) atoms. In the second Cu site, Cu(2) is bonded in a 9-coordinate geometry to one Cu(2), one Cu(3), one Cu(4), one Sn(2), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(5) atoms. In the third Cu site, Cu(3) is bonded in a 10-coordinate geometry to one Cu(1), one Cu(2), one Cu(3), one Cu(4), one Sn(1), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(4) atoms. In the fourth Cu site, Cu(4) is bonded in a 11-coordinate geometry to one Cu(2), one Cu(3), one Cu(5), one Cu(6), one Cu(7), one Cu(8), one Sn(3), one Sn(4), one Sn(5), one Sn(6), and one Sn(7) atom. In the fifth Cu site, Cu(5) is bonded in a distorted q6 geometry to one Cu(4), one Cu(6), one Cu(8), one Sn(2), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(5) atoms. In the sixth Cu site, Cu(6) is bonded in a distorted q6 geometry to one Cu(1), one Cu(4), one Cu(5), one Cu(7), one Sn(1), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(4) atoms. In the seventh Cu site, Cu(7) is bonded in a 10-coordinate geometry to one Cu(1), one Cu(4), one Cu(6), one Cu(8), one Sn(1), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(4) atoms. In the eighth Cu site, Cu(8) is bonded in a distorted q6 geometry to one Cu(4), one Cu(5), one Cu(7), one Sn(2), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(5) atoms. There are seven inequivalent Sn sites. In the first Sn site, Sn(3) is bonded in a 7-coordinate geometry to one Cu(2), one Cu(3), one Cu(4), one Cu(5), one Cu(6), one Cu(7), and one Cu(8) atom. In the second Sn site, Sn(4) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(4), two equivalent Cu(3), two equivalent Cu(6), and two equivalent Cu(7) atoms. In the third Sn site, Sn(5) is bonded in a 7-coordinate geometry to one Cu(4), two equivalent Cu(2), two equivalent Cu(5), and two equivalent Cu(8) atoms. In the fourth Sn site, Sn(6) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(2), one Cu(3), one Cu(4), one Cu(5), one Cu(6), one Cu(7), and one Cu(8) atom. In the fifth Sn site, Sn(7) is bonded in a 7-coordinate geometry to one Cu(2), one Cu(3), one Cu(4), one Cu(5), one Cu(6), one Cu(7), and one Cu(8) atom. In the sixth Sn site, Sn(1) is bonded in a 7-coordinate geometry to one Cu(1), two equivalent Cu(3), two equivalent Cu(6), and two equivalent Cu(7) atoms. In the seventh Sn site, Sn(2) is bonded in a 6-coordinate geometry to two equivalent Cu(2), two equivalent Cu(5), and two equivalent Cu(8) atoms.
Cu5Sn4 crystallizes in the monoclinic C2 space group. There are eight inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 11-coordinate geometry to two equivalent Cu(3), two equivalent Cu(6), two equivalent Cu(7), one Sn(1), two equivalent Sn(4), and two equivalent Sn(6) atoms. Both Cu(1)-Cu(3) bond lengths are 2.66 Å. Both Cu(1)-Cu(6) bond lengths are 2.72 Å. Both Cu(1)-Cu(7) bond lengths are 2.62 Å. The Cu(1)-Sn(1) bond length is 2.61 Å. Both Cu(1)-Sn(4) bond lengths are 2.65 Å. Both Cu(1)-Sn(6) bond lengths are 2.73 Å. In the second Cu site, Cu(2) is bonded in a 9-coordinate geometry to one Cu(2), one Cu(3), one Cu(4), one Sn(2), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(5) atoms. The Cu(2)-Cu(2) bond length is 2.50 Å. The Cu(2)-Cu(3) bond length is 2.54 Å. The Cu(2)-Cu(4) bond length is 2.68 Å. The Cu(2)-Sn(2) bond length is 2.75 Å. The Cu(2)-Sn(3) bond length is 2.77 Å. The Cu(2)-Sn(6) bond length is 2.76 Å. The Cu(2)-Sn(7) bond length is 2.69 Å. There is one shorter (2.72 Å) and one longer (2.77 Å) Cu(2)-Sn(5) bond length. In the third Cu site, Cu(3) is bonded in a 10-coordinate geometry to one Cu(1), one Cu(2), one Cu(3), one Cu(4), one Sn(1), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(4) atoms. The Cu(3)-Cu(3) bond length is 2.57 Å. The Cu(3)-Cu(4) bond length is 2.65 Å. The Cu(3)-Sn(1) bond length is 2.70 Å. The Cu(3)-Sn(3) bond length is 2.84 Å. The Cu(3)-Sn(6) bond length is 2.81 Å. The Cu(3)-Sn(7) bond length is 2.69 Å. Both Cu(3)-Sn(4) bond lengths are 2.79 Å. In the fourth Cu site, Cu(4) is bonded in a 11-coordinate geometry to one Cu(2), one Cu(3), one Cu(5), one Cu(6), one Cu(7), one Cu(8), one Sn(3), one Sn(4), one Sn(5), one Sn(6), and one Sn(7) atom. The Cu(4)-Cu(5) bond length is 2.63 Å. The Cu(4)-Cu(6) bond length is 2.70 Å. The Cu(4)-Cu(7) bond length is 2.63 Å. The Cu(4)-Cu(8) bond length is 2.68 Å. The Cu(4)-Sn(3) bond length is 2.61 Å. The Cu(4)-Sn(4) bond length is 2.74 Å. The Cu(4)-Sn(5) bond length is 2.73 Å. The Cu(4)-Sn(6) bond length is 2.66 Å. The Cu(4)-Sn(7) bond length is 2.62 Å. In the fifth Cu site, Cu(5) is bonded in a distorted q6 geometry to one Cu(4), one Cu(6), one Cu(8), one Sn(2), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(5) atoms. The Cu(5)-Cu(6) bond length is 2.55 Å. The Cu(5)-Cu(8) bond length is 2.50 Å. The Cu(5)-Sn(2) bond length is 2.82 Å. The Cu(5)-Sn(3) bond length is 2.85 Å. The Cu(5)-Sn(6) bond length is 2.62 Å. The Cu(5)-Sn(7) bond length is 2.79 Å. There is one shorter (2.71 Å) and one longer (2.72 Å) Cu(5)-Sn(5) bond length. In the sixth Cu site, Cu(6) is bonded in a distorted q6 geometry to one Cu(1), one Cu(4), one Cu(5), one Cu(7), one Sn(1), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(4) atoms. The Cu(6)-Cu(7) bond length is 2.56 Å. The Cu(6)-Sn(1) bond length is 2.84 Å. The Cu(6)-Sn(3) bond length is 2.86 Å. The Cu(6)-Sn(6) bond length is 2.72 Å. The Cu(6)-Sn(7) bond length is 2.80 Å. There is one shorter (2.72 Å) and one longer (2.76 Å) Cu(6)-Sn(4) bond length. In the seventh Cu site, Cu(7) is bonded in a 10-coordinate geometry to one Cu(1), one Cu(4), one Cu(6), one Cu(8), one Sn(1), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(4) atoms. The Cu(7)-Cu(8) bond length is 2.54 Å. The Cu(7)-Sn(1) bond length is 2.90 Å. The Cu(7)-Sn(3) bond length is 2.70 Å. The Cu(7)-Sn(6) bond length is 2.75 Å. The Cu(7)-Sn(7) bond length is 2.89 Å. There is one shorter (2.64 Å) and one longer (2.80 Å) Cu(7)-Sn(4) bond length. In the eighth Cu site, Cu(8) is bonded in a distorted q6 geometry to one Cu(4), one Cu(5), one Cu(7), one Sn(2), one Sn(3), one Sn(6), one Sn(7), and two equivalent Sn(5) atoms. The Cu(8)-Sn(2) bond length is 2.80 Å. The Cu(8)-Sn(3) bond length is 2.69 Å. The Cu(8)-Sn(6) bond length is 2.70 Å. The Cu(8)-Sn(7) bond length is 2.83 Å. There is one shorter (2.68 Å) and one longer (2.76 Å) Cu(8)-Sn(5) bond length. There are seven inequivalent Sn sites. In the first Sn site, Sn(3) is bonded in a 7-coordinate geometry to one Cu(2), one Cu(3), one Cu(4), one Cu(5), one Cu(6), one Cu(7), and one Cu(8) atom. In the second Sn site, Sn(4) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(4), two equivalent Cu(3), two equivalent Cu(6), and two equivalent Cu(7) atoms. In the third Sn site, Sn(5) is bonded in a 7-coordinate geometry to one Cu(4), two equivalent Cu(2), two equivalent Cu(5), and two equivalent Cu(8) atoms. In the fourth Sn site, Sn(6) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(2), one Cu(3), one Cu(4), one Cu(5), one Cu(6), one Cu(7), and one Cu(8) atom. In the fifth Sn site, Sn(7) is bonded in a 7-coordinate geometry to one Cu(2), one Cu(3), one Cu(4), one Cu(5), one Cu(6), one Cu(7), and one Cu(8) atom. In the sixth Sn site, Sn(1) is bonded in a 7-coordinate geometry to one Cu(1), two equivalent Cu(3), two equivalent Cu(6), and two equivalent Cu(7) atoms. In the seventh Sn site, Sn(2) is bonded in a 6-coordinate geometry to two equivalent Cu(2), two equivalent Cu(5), and two equivalent Cu(8) atoms.