Au4Sn9 crystallizes in the monoclinic Cm space group. There are six inequivalent Au sites. In the first Au site, Au(1) is bonded in a 8-coordinate geometry to one Au(3), two equivalent Au(6), one Sn(1), one Sn(2), one Sn(4), one Sn(6), two equivalent Sn(7), and two equivalent Sn(8) atoms. In the second Au site, Au(2) is bonded in a 5-coordinate geometry to one Au(6), one Sn(10), one Sn(11), one Sn(2), one Sn(3), one Sn(5), and one Sn(7) atom. In the third Au site, Au(3) is bonded in a 13-coordinate geometry to one Au(1), one Au(4), one Au(5), one Sn(4), one Sn(6), two equivalent Sn(10), two equivalent Sn(3), two equivalent Sn(8), and two equivalent Sn(9) atoms. In the fourth Au site, Au(4) is bonded in a 9-coordinate geometry to one Au(3), one Sn(2), one Sn(4), one Sn(6), two equivalent Sn(10), two equivalent Sn(3), and two equivalent Sn(5) atoms. In the fifth Au site, Au(5) is bonded in a 12-coordinate geometry to one Au(3), one Sn(1), one Sn(4), one Sn(6), two equivalent Sn(11), two equivalent Sn(3), two equivalent Sn(7), and two equivalent Sn(9) atoms. In the sixth Au site, Au(6) is bonded in a 12-coordinate geometry to one Au(1), one Au(2), one Sn(1), one Sn(10), one Sn(11), one Sn(2), one Sn(3), one Sn(5), one Sn(7), one Sn(9), and two equivalent Sn(8) atoms. There are eleven inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 3-coordinate geometry to one Au(1), one Au(5), two equivalent Au(6), and one Sn(2) atom. In the second Sn site, Sn(2) is bonded in a 12-coordinate geometry to one Au(1), one Au(4), two equivalent Au(2), two equivalent Au(6), one Sn(1), one Sn(6), two equivalent Sn(3), and two equivalent Sn(7) atoms. In the third Sn site, Sn(3) is bonded in a 5-coordinate geometry to one Au(2), one Au(3), one Au(4), one Au(5), one Au(6), and one Sn(2) atom. In the fourth Sn site, Sn(4) is bonded in a 8-coordinate geometry to one Au(1), one Au(3), one Au(4), one Au(5), two equivalent Sn(10), and two equivalent Sn(7) atoms. In the fifth Sn site, Sn(5) is bonded in a 3-coordinate geometry to one Au(2), one Au(4), one Au(6), and one Sn(6) atom. In the sixth Sn site, Sn(6) is bonded in a 9-coordinate geometry to one Au(1), one Au(3), one Au(4), one Au(5), one Sn(2), two equivalent Sn(5), and two equivalent Sn(9) atoms. In the seventh Sn site, Sn(7) is bonded in a 10-coordinate geometry to one Au(1), one Au(2), one Au(5), one Au(6), one Sn(10), one Sn(11), one Sn(2), one Sn(4), one Sn(8), and one Sn(9) atom. In the eighth Sn site, Sn(8) is bonded in a 4-coordinate geometry to one Au(1), one Au(3), two equivalent Au(6), and one Sn(7) atom. In the ninth Sn site, Sn(9) is bonded in a 2-coordinate geometry to one Au(3), one Au(5), one Au(6), one Sn(6), and one Sn(7) atom. In the tenth Sn site, Sn(10) is bonded in a 3-coordinate geometry to one Au(2), one Au(3), one Au(4), one Au(6), one Sn(4), and one Sn(7) atom. In the eleventh Sn site, Sn(11) is bonded in a distorted single-bond geometry to one Au(2), one Au(5), one Au(6), and one Sn(7) atom.
Au4Sn9 crystallizes in the monoclinic Cm space group. There are six inequivalent Au sites. In the first Au site, Au(1) is bonded in a 8-coordinate geometry to one Au(3), two equivalent Au(6), one Sn(1), one Sn(2), one Sn(4), one Sn(6), two equivalent Sn(7), and two equivalent Sn(8) atoms. The Au(1)-Au(3) bond length is 3.16 Å. Both Au(1)-Au(6) bond lengths are 3.35 Å. The Au(1)-Sn(1) bond length is 3.03 Å. The Au(1)-Sn(2) bond length is 3.24 Å. The Au(1)-Sn(4) bond length is 3.34 Å. The Au(1)-Sn(6) bond length is 3.26 Å. Both Au(1)-Sn(7) bond lengths are 3.35 Å. Both Au(1)-Sn(8) bond lengths are 2.90 Å. In the second Au site, Au(2) is bonded in a 5-coordinate geometry to one Au(6), one Sn(10), one Sn(11), one Sn(2), one Sn(3), one Sn(5), and one Sn(7) atom. The Au(2)-Au(6) bond length is 3.26 Å. The Au(2)-Sn(10) bond length is 2.96 Å. The Au(2)-Sn(11) bond length is 3.04 Å. The Au(2)-Sn(2) bond length is 3.10 Å. The Au(2)-Sn(3) bond length is 3.03 Å. The Au(2)-Sn(5) bond length is 2.97 Å. The Au(2)-Sn(7) bond length is 3.43 Å. In the third Au site, Au(3) is bonded in a 13-coordinate geometry to one Au(1), one Au(4), one Au(5), one Sn(4), one Sn(6), two equivalent Sn(10), two equivalent Sn(3), two equivalent Sn(8), and two equivalent Sn(9) atoms. The Au(3)-Au(4) bond length is 3.36 Å. The Au(3)-Au(5) bond length is 3.30 Å. The Au(3)-Sn(4) bond length is 2.92 Å. The Au(3)-Sn(6) bond length is 2.92 Å. Both Au(3)-Sn(10) bond lengths are 3.50 Å. Both Au(3)-Sn(3) bond lengths are 3.15 Å. Both Au(3)-Sn(8) bond lengths are 3.32 Å. Both Au(3)-Sn(9) bond lengths are 3.35 Å. In the fourth Au site, Au(4) is bonded in a 9-coordinate geometry to one Au(3), one Sn(2), one Sn(4), one Sn(6), two equivalent Sn(10), two equivalent Sn(3), and two equivalent Sn(5) atoms. The Au(4)-Sn(2) bond length is 3.24 Å. The Au(4)-Sn(4) bond length is 3.17 Å. The Au(4)-Sn(6) bond length is 3.29 Å. Both Au(4)-Sn(10) bond lengths are 3.27 Å. Both Au(4)-Sn(3) bond lengths are 3.09 Å. Both Au(4)-Sn(5) bond lengths are 3.01 Å. In the fifth Au site, Au(5) is bonded in a 12-coordinate geometry to one Au(3), one Sn(1), one Sn(4), one Sn(6), two equivalent Sn(11), two equivalent Sn(3), two equivalent Sn(7), and two equivalent Sn(9) atoms. The Au(5)-Sn(1) bond length is 3.44 Å. The Au(5)-Sn(4) bond length is 3.23 Å. The Au(5)-Sn(6) bond length is 3.22 Å. Both Au(5)-Sn(11) bond lengths are 3.40 Å. Both Au(5)-Sn(3) bond lengths are 3.31 Å. Both Au(5)-Sn(7) bond lengths are 3.17 Å. Both Au(5)-Sn(9) bond lengths are 3.02 Å. In the sixth Au site, Au(6) is bonded in a 12-coordinate geometry to one Au(1), one Au(2), one Sn(1), one Sn(10), one Sn(11), one Sn(2), one Sn(3), one Sn(5), one Sn(7), one Sn(9), and two equivalent Sn(8) atoms. The Au(6)-Sn(1) bond length is 3.10 Å. The Au(6)-Sn(10) bond length is 3.05 Å. The Au(6)-Sn(11) bond length is 3.40 Å. The Au(6)-Sn(2) bond length is 3.27 Å. The Au(6)-Sn(3) bond length is 3.29 Å. The Au(6)-Sn(5) bond length is 3.26 Å. The Au(6)-Sn(7) bond length is 3.05 Å. The Au(6)-Sn(9) bond length is 3.16 Å. There is one shorter (3.20 Å) and one longer (3.28 Å) Au(6)-Sn(8) bond length. There are eleven inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 3-coordinate geometry to one Au(1), one Au(5), two equivalent Au(6), and one Sn(2) atom. The Sn(1)-Sn(2) bond length is 3.19 Å. In the second Sn site, Sn(2) is bonded in a 12-coordinate geometry to one Au(1), one Au(4), two equivalent Au(2), two equivalent Au(6), one Sn(1), one Sn(6), two equivalent Sn(3), and two equivalent Sn(7) atoms. The Sn(2)-Sn(6) bond length is 3.32 Å. Both Sn(2)-Sn(3) bond lengths are 3.31 Å. Both Sn(2)-Sn(7) bond lengths are 3.14 Å. In the third Sn site, Sn(3) is bonded in a 5-coordinate geometry to one Au(2), one Au(3), one Au(4), one Au(5), one Au(6), and one Sn(2) atom. In the fourth Sn site, Sn(4) is bonded in a 8-coordinate geometry to one Au(1), one Au(3), one Au(4), one Au(5), two equivalent Sn(10), and two equivalent Sn(7) atoms. Both Sn(4)-Sn(10) bond lengths are 3.23 Å. Both Sn(4)-Sn(7) bond lengths are 3.27 Å. In the fifth Sn site, Sn(5) is bonded in a 3-coordinate geometry to one Au(2), one Au(4), one Au(6), and one Sn(6) atom. The Sn(5)-Sn(6) bond length is 3.17 Å. In the sixth Sn site, Sn(6) is bonded in a 9-coordinate geometry to one Au(1), one Au(3), one Au(4), one Au(5), one Sn(2), two equivalent Sn(5), and two equivalent Sn(9) atoms. Both Sn(6)-Sn(9) bond lengths are 3.20 Å. In the seventh Sn site, Sn(7) is bonded in a 10-coordinate geometry to one Au(1), one Au(2), one Au(5), one Au(6), one Sn(10), one Sn(11), one Sn(2), one Sn(4), one Sn(8), and one Sn(9) atom. The Sn(7)-Sn(10) bond length is 3.20 Å. The Sn(7)-Sn(11) bond length is 3.21 Å. The Sn(7)-Sn(8) bond length is 3.17 Å. The Sn(7)-Sn(9) bond length is 3.26 Å. In the eighth Sn site, Sn(8) is bonded in a 4-coordinate geometry to one Au(1), one Au(3), two equivalent Au(6), and one Sn(7) atom. In the ninth Sn site, Sn(9) is bonded in a 2-coordinate geometry to one Au(3), one Au(5), one Au(6), one Sn(6), and one Sn(7) atom. In the tenth Sn site, Sn(10) is bonded in a 3-coordinate geometry to one Au(2), one Au(3), one Au(4), one Au(6), one Sn(4), and one Sn(7) atom. In the eleventh Sn site, Sn(11) is bonded in a distorted single-bond geometry to one Au(2), one Au(5), one Au(6), and one Sn(7) atom.