Sr11Cd6Sb12 crystallizes in the monoclinic C2/m space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to two equivalent Cd(1), two equivalent Cd(2), two equivalent Sb(1), and four equivalent Sb(2) atoms. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one Cd(3), one Sb(5), one Sb(6), two equivalent Sb(2), and two equivalent Sb(4) atoms. In the third Sr site, Sr(3) is bonded to one Sb(5), one Sb(6), two equivalent Sb(1), and two equivalent Sb(3) atoms to form SrSb6 octahedra that share corners with two equivalent Sr(6)Cd4Sb6 octahedra, edges with two equivalent Sr(3)Sb6 octahedra, and  a faceface with one Sr(6)Cd4Sb6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to three equivalent Cd(3), one Sb(6), two equivalent Sb(3), and three equivalent Sb(4) atoms. In the fifth Sr site, Sr(5) is bonded in a 7-coordinate geometry to two equivalent Cd(3), two equivalent Sb(5), and three equivalent Sb(3) atoms. In the sixth Sr site, Sr(6) is bonded to four equivalent Cd(1), two equivalent Sb(6), and four equivalent Sb(1) atoms to form distorted SrCd4Sb6 octahedra that share corners with four equivalent Sr(3)Sb6 octahedra, faces with two equivalent Sr(6)Cd4Sb6 octahedra, and faces with two equivalent Sr(3)Sb6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Sr(6), one Sb(1), one Sb(2), and two equivalent Sb(6) atoms. In the second Cd site, Cd(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), one Sb(1), one Sb(2), and two equivalent Sb(5) atoms. In the third Cd site, Cd(3) is bonded in a 10-coordinate geometry to one Sr(2), two equivalent Sr(5), three equivalent Sr(4), one Sb(3), one Sb(5), and two equivalent Sb(4) atoms. There are six inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), two equivalent Sr(6), one Cd(1), and one Cd(2) atom. In the second Sb site, Sb(2) is bonded in a 9-coordinate geometry to two equivalent Sr(2), four equivalent Sr(1), one Cd(1), one Cd(2), and one Sb(2) atom. In the third Sb site, Sb(3) is bonded in a 8-coordinate geometry to two equivalent Sr(3), two equivalent Sr(4), three equivalent Sr(5), and one Cd(3) atom. In the fourth Sb site, Sb(4) is bonded in a 7-coordinate geometry to two equivalent Sr(2), three equivalent Sr(4), and two equivalent Cd(3) atoms. In the fifth Sb site, Sb(5) is bonded in a 7-coordinate geometry to one Sr(2), one Sr(3), two equivalent Sr(5), one Cd(3), and two equivalent Cd(2) atoms. In the sixth Sb site, Sb(6) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Sr(6), and two equivalent Cd(1) atoms.
Sr11Cd6Sb12 crystallizes in the monoclinic C2/m space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to two equivalent Cd(1), two equivalent Cd(2), two equivalent Sb(1), and four equivalent Sb(2) atoms. Both Sr(1)-Cd(1) bond lengths are 3.62 Å. Both Sr(1)-Cd(2) bond lengths are 3.52 Å. Both Sr(1)-Sb(1) bond lengths are 3.43 Å. There are two shorter (3.49 Å) and two longer (3.61 Å) Sr(1)-Sb(2) bond lengths. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one Cd(3), one Sb(5), one Sb(6), two equivalent Sb(2), and two equivalent Sb(4) atoms. The Sr(2)-Cd(3) bond length is 3.42 Å. The Sr(2)-Sb(5) bond length is 3.33 Å. The Sr(2)-Sb(6) bond length is 3.30 Å. Both Sr(2)-Sb(2) bond lengths are 3.36 Å. Both Sr(2)-Sb(4) bond lengths are 3.47 Å. In the third Sr site, Sr(3) is bonded to one Sb(5), one Sb(6), two equivalent Sb(1), and two equivalent Sb(3) atoms to form SrSb6 octahedra that share corners with two equivalent Sr(6)Cd4Sb6 octahedra, edges with two equivalent Sr(3)Sb6 octahedra, and  a faceface with one Sr(6)Cd4Sb6 octahedra. The corner-sharing octahedral tilt angles are 50°. The Sr(3)-Sb(5) bond length is 3.32 Å. The Sr(3)-Sb(6) bond length is 3.38 Å. Both Sr(3)-Sb(1) bond lengths are 3.56 Å. Both Sr(3)-Sb(3) bond lengths are 3.51 Å. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to three equivalent Cd(3), one Sb(6), two equivalent Sb(3), and three equivalent Sb(4) atoms. There are two shorter (3.64 Å) and one longer (3.96 Å) Sr(4)-Cd(3) bond length. The Sr(4)-Sb(6) bond length is 3.47 Å. Both Sr(4)-Sb(3) bond lengths are 3.63 Å. There is one shorter (3.43 Å) and two longer (3.48 Å) Sr(4)-Sb(4) bond lengths. In the fifth Sr site, Sr(5) is bonded in a 7-coordinate geometry to two equivalent Cd(3), two equivalent Sb(5), and three equivalent Sb(3) atoms. Both Sr(5)-Cd(3) bond lengths are 3.49 Å. Both Sr(5)-Sb(5) bond lengths are 3.31 Å. There are two shorter (3.44 Å) and one longer (3.65 Å) Sr(5)-Sb(3) bond length. In the sixth Sr site, Sr(6) is bonded to four equivalent Cd(1), two equivalent Sb(6), and four equivalent Sb(1) atoms to form distorted SrCd4Sb6 octahedra that share corners with four equivalent Sr(3)Sb6 octahedra, faces with two equivalent Sr(6)Cd4Sb6 octahedra, and faces with two equivalent Sr(3)Sb6 octahedra. The corner-sharing octahedral tilt angles are 50°. All Sr(6)-Cd(1) bond lengths are 3.84 Å. Both Sr(6)-Sb(6) bond lengths are 3.43 Å. All Sr(6)-Sb(1) bond lengths are 3.46 Å. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Sr(6), one Sb(1), one Sb(2), and two equivalent Sb(6) atoms. The Cd(1)-Sb(1) bond length is 3.01 Å. The Cd(1)-Sb(2) bond length is 3.32 Å. Both Cd(1)-Sb(6) bond lengths are 2.83 Å. In the second Cd site, Cd(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), one Sb(1), one Sb(2), and two equivalent Sb(5) atoms. The Cd(2)-Sb(1) bond length is 2.93 Å. The Cd(2)-Sb(2) bond length is 3.06 Å. Both Cd(2)-Sb(5) bond lengths are 2.87 Å. In the third Cd site, Cd(3) is bonded in a 10-coordinate geometry to one Sr(2), two equivalent Sr(5), three equivalent Sr(4), one Sb(3), one Sb(5), and two equivalent Sb(4) atoms. The Cd(3)-Sb(3) bond length is 2.91 Å. The Cd(3)-Sb(5) bond length is 3.14 Å. Both Cd(3)-Sb(4) bond lengths are 2.94 Å. There are six inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), two equivalent Sr(6), one Cd(1), and one Cd(2) atom. In the second Sb site, Sb(2) is bonded in a 9-coordinate geometry to two equivalent Sr(2), four equivalent Sr(1), one Cd(1), one Cd(2), and one Sb(2) atom. The Sb(2)-Sb(2) bond length is 2.87 Å. In the third Sb site, Sb(3) is bonded in a 8-coordinate geometry to two equivalent Sr(3), two equivalent Sr(4), three equivalent Sr(5), and one Cd(3) atom. In the fourth Sb site, Sb(4) is bonded in a 7-coordinate geometry to two equivalent Sr(2), three equivalent Sr(4), and two equivalent Cd(3) atoms. In the fifth Sb site, Sb(5) is bonded in a 7-coordinate geometry to one Sr(2), one Sr(3), two equivalent Sr(5), one Cd(3), and two equivalent Cd(2) atoms. In the sixth Sb site, Sb(6) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Sr(6), and two equivalent Cd(1) atoms.