K4Cu8Te11 crystallizes in the monoclinic C2/m space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one Te(7), two equivalent Te(3), two equivalent Te(6), and three equivalent Te(1) atoms. In the second K site, K(2) is bonded in a 16-coordinate geometry to two equivalent Cu(4), four equivalent Cu(3), one Te(8), two equivalent Te(2), two equivalent Te(3), two equivalent Te(5), and three equivalent Te(4) atoms. In the third K site, K(3) is bonded in a 10-coordinate geometry to two equivalent Cu(4), two equivalent Te(2), two equivalent Te(3), two equivalent Te(5), and two equivalent Te(6) atoms. In the fourth K site, K(4) is bonded in a 20-coordinate geometry to two equivalent Cu(1), two equivalent Cu(2), two equivalent Cu(3), two equivalent Cu(4), one Te(4), one Te(5), two equivalent Te(3), two equivalent Te(6), two equivalent Te(7), two equivalent Te(8), and two equivalent Te(9) atoms. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 4-coordinate geometry to one K(4), one Te(1), one Te(3), one Te(7), and one Te(9) atom. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to one K(4), one Te(1), one Te(6), one Te(7), and one Te(9) atom. In the third Cu site, Cu(3) is bonded in a 8-coordinate geometry to one K(4), two equivalent K(2), one Cu(3), one Te(3), one Te(8), and two equivalent Te(4) atoms. In the fourth Cu site, Cu(4) is bonded in a 8-coordinate geometry to one K(2), one K(3), one K(4), one Cu(4), one Te(2), one Te(5), one Te(6), and one Te(8) atom. There are nine inequivalent Te sites. In the first Te site, Te(7) is bonded in a 8-coordinate geometry to one K(1), two equivalent K(4), two equivalent Cu(1), two equivalent Cu(2), and one Te(7) atom. In the second Te site, Te(8) is bonded in a 8-coordinate geometry to one K(2), two equivalent K(4), two equivalent Cu(3), two equivalent Cu(4), and one Te(9) atom. In the third Te site, Te(5) is bonded in a 3-coordinate geometry to one K(4), two equivalent K(2), two equivalent K(3), and two equivalent Cu(4) atoms. In the fourth Te site, Te(9) is bonded in a 7-coordinate geometry to two equivalent K(4), two equivalent Cu(1), two equivalent Cu(2), and one Te(8) atom. In the fifth Te site, Te(6) is bonded in a 6-coordinate geometry to one K(1), one K(3), one K(4), one Cu(2), one Cu(4), and one Te(6) atom. In the sixth Te site, Te(1) is bonded to three equivalent K(1), two equivalent Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing TeK3Cu4 pentagonal bipyramids. In the seventh Te site, Te(2) is bonded in a 7-coordinate geometry to two equivalent K(2), two equivalent K(3), two equivalent Cu(4), and one Te(2) atom. In the eighth Te site, Te(3) is bonded in a 7-coordinate geometry to one K(1), one K(2), one K(3), one K(4), one Cu(1), one Cu(3), and one Te(3) atom. In the ninth Te site, Te(4) is bonded in a 4-coordinate geometry to one K(4), three equivalent K(2), and four equivalent Cu(3) atoms.
K4Cu8Te11 crystallizes in the monoclinic C2/m space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one Te(7), two equivalent Te(3), two equivalent Te(6), and three equivalent Te(1) atoms. The K(1)-Te(7) bond length is 3.88 Å. Both K(1)-Te(3) bond lengths are 4.06 Å. Both K(1)-Te(6) bond lengths are 3.75 Å. There are two shorter (3.66 Å) and one longer (3.77 Å) K(1)-Te(1) bond length. In the second K site, K(2) is bonded in a 16-coordinate geometry to two equivalent Cu(4), four equivalent Cu(3), one Te(8), two equivalent Te(2), two equivalent Te(3), two equivalent Te(5), and three equivalent Te(4) atoms. Both K(2)-Cu(4) bond lengths are 3.52 Å. There are two shorter (3.72 Å) and two longer (3.82 Å) K(2)-Cu(3) bond lengths. The K(2)-Te(8) bond length is 3.44 Å. There is one shorter (3.39 Å) and one longer (3.80 Å) K(2)-Te(2) bond length. Both K(2)-Te(3) bond lengths are 3.53 Å. Both K(2)-Te(5) bond lengths are 3.81 Å. There is one shorter (3.74 Å) and two longer (4.02 Å) K(2)-Te(4) bond lengths. In the third K site, K(3) is bonded in a 10-coordinate geometry to two equivalent Cu(4), two equivalent Te(2), two equivalent Te(3), two equivalent Te(5), and two equivalent Te(6) atoms. Both K(3)-Cu(4) bond lengths are 3.78 Å. Both K(3)-Te(2) bond lengths are 3.81 Å. Both K(3)-Te(3) bond lengths are 3.69 Å. There is one shorter (3.67 Å) and one longer (3.95 Å) K(3)-Te(5) bond length. Both K(3)-Te(6) bond lengths are 3.61 Å. In the fourth K site, K(4) is bonded in a 20-coordinate geometry to two equivalent Cu(1), two equivalent Cu(2), two equivalent Cu(3), two equivalent Cu(4), one Te(4), one Te(5), two equivalent Te(3), two equivalent Te(6), two equivalent Te(7), two equivalent Te(8), and two equivalent Te(9) atoms. Both K(4)-Cu(1) bond lengths are 3.76 Å. Both K(4)-Cu(2) bond lengths are 3.72 Å. Both K(4)-Cu(3) bond lengths are 3.71 Å. Both K(4)-Cu(4) bond lengths are 3.72 Å. The K(4)-Te(4) bond length is 3.84 Å. The K(4)-Te(5) bond length is 3.96 Å. Both K(4)-Te(3) bond lengths are 3.81 Å. Both K(4)-Te(6) bond lengths are 3.74 Å. There is one shorter (3.77 Å) and one longer (3.83 Å) K(4)-Te(7) bond length. Both K(4)-Te(8) bond lengths are 3.70 Å. Both K(4)-Te(9) bond lengths are 3.75 Å. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 4-coordinate geometry to one K(4), one Te(1), one Te(3), one Te(7), and one Te(9) atom. The Cu(1)-Te(1) bond length is 2.64 Å. The Cu(1)-Te(3) bond length is 2.60 Å. The Cu(1)-Te(7) bond length is 2.63 Å. The Cu(1)-Te(9) bond length is 2.67 Å. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to one K(4), one Te(1), one Te(6), one Te(7), and one Te(9) atom. The Cu(2)-Te(1) bond length is 2.63 Å. The Cu(2)-Te(6) bond length is 2.61 Å. The Cu(2)-Te(7) bond length is 2.64 Å. The Cu(2)-Te(9) bond length is 2.68 Å. In the third Cu site, Cu(3) is bonded in a 8-coordinate geometry to one K(4), two equivalent K(2), one Cu(3), one Te(3), one Te(8), and two equivalent Te(4) atoms. The Cu(3)-Cu(3) bond length is 2.60 Å. The Cu(3)-Te(3) bond length is 2.57 Å. The Cu(3)-Te(8) bond length is 2.64 Å. There is one shorter (2.64 Å) and one longer (2.70 Å) Cu(3)-Te(4) bond length. In the fourth Cu site, Cu(4) is bonded in a 8-coordinate geometry to one K(2), one K(3), one K(4), one Cu(4), one Te(2), one Te(5), one Te(6), and one Te(8) atom. The Cu(4)-Cu(4) bond length is 2.79 Å. The Cu(4)-Te(2) bond length is 2.61 Å. The Cu(4)-Te(5) bond length is 2.59 Å. The Cu(4)-Te(6) bond length is 2.60 Å. The Cu(4)-Te(8) bond length is 2.71 Å. There are nine inequivalent Te sites. In the first Te site, Te(7) is bonded in a 8-coordinate geometry to one K(1), two equivalent K(4), two equivalent Cu(1), two equivalent Cu(2), and one Te(7) atom. The Te(7)-Te(7) bond length is 2.93 Å. In the second Te site, Te(8) is bonded in a 8-coordinate geometry to one K(2), two equivalent K(4), two equivalent Cu(3), two equivalent Cu(4), and one Te(9) atom. The Te(8)-Te(9) bond length is 2.93 Å. In the third Te site, Te(5) is bonded in a 3-coordinate geometry to one K(4), two equivalent K(2), two equivalent K(3), and two equivalent Cu(4) atoms. In the fourth Te site, Te(9) is bonded in a 7-coordinate geometry to two equivalent K(4), two equivalent Cu(1), two equivalent Cu(2), and one Te(8) atom. In the fifth Te site, Te(6) is bonded in a 6-coordinate geometry to one K(1), one K(3), one K(4), one Cu(2), one Cu(4), and one Te(6) atom. The Te(6)-Te(6) bond length is 2.86 Å. In the sixth Te site, Te(1) is bonded to three equivalent K(1), two equivalent Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing TeK3Cu4 pentagonal bipyramids. In the seventh Te site, Te(2) is bonded in a 7-coordinate geometry to two equivalent K(2), two equivalent K(3), two equivalent Cu(4), and one Te(2) atom. The Te(2)-Te(2) bond length is 2.91 Å. In the eighth Te site, Te(3) is bonded in a 7-coordinate geometry to one K(1), one K(2), one K(3), one K(4), one Cu(1), one Cu(3), and one Te(3) atom. The Te(3)-Te(3) bond length is 2.88 Å. In the ninth Te site, Te(4) is bonded in a 4-coordinate geometry to one K(4), three equivalent K(2), and four equivalent Cu(3) atoms.