Yb11(SnBi4)2 crystallizes in the tetragonal I4/mmm space group. There are four inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 9-coordinate geometry to four equivalent Sn(1), one Bi(3), and four equivalent Bi(4) atoms. In the second Yb site, Yb(2) is bonded in a 7-coordinate geometry to two equivalent Sn(1), one Bi(1), two equivalent Bi(2), and two equivalent Bi(4) atoms. In the third Yb site, Yb(3) is bonded to one Bi(1), one Bi(2), one Bi(3), and four equivalent Bi(4) atoms to form distorted YbBi7 pentagonal bipyramids that share corners with three equivalent Yb(3)Bi7 pentagonal bipyramids, corners with four equivalent Yb(4)SnBi6 pentagonal bipyramids, edges with two equivalent Yb(3)Bi7 pentagonal bipyramids, faces with two equivalent Yb(4)SnBi6 pentagonal bipyramids, and faces with four equivalent Yb(3)Bi7 pentagonal bipyramids. In the fourth Yb site, Yb(4) is bonded to one Sn(1), two equivalent Bi(2), two equivalent Bi(3), and two equivalent Bi(4) atoms to form distorted YbSnBi6 pentagonal bipyramids that share corners with eight equivalent Yb(3)Bi7 pentagonal bipyramids,  an edgeedge with one Yb(4)SnBi6 pentagonal bipyramid, faces with two equivalent Yb(4)SnBi6 pentagonal bipyramids, and faces with four equivalent Yb(3)Bi7 pentagonal bipyramids. Sn(1) is bonded in a 11-coordinate geometry to one Yb(4), two equivalent Yb(1), four equivalent Yb(2), two equivalent Sn(1), and two equivalent Bi(4) atoms. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 8-coordinate geometry to four equivalent Yb(2) and four equivalent Yb(3) atoms. In the second Bi site, Bi(2) is bonded in a 8-coordinate geometry to two equivalent Yb(3), two equivalent Yb(4), and four equivalent Yb(2) atoms. In the third Bi site, Bi(3) is bonded in a 9-coordinate geometry to one Yb(1), four equivalent Yb(3), and four equivalent Yb(4) atoms. In the fourth Bi site, Bi(4) is bonded in a 10-coordinate geometry to one Yb(1), one Yb(4), two equivalent Yb(2), four equivalent Yb(3), one Sn(1), and one Bi(4) atom.
Yb11(SnBi4)2 crystallizes in the tetragonal I4/mmm space group. There are four inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 9-coordinate geometry to four equivalent Sn(1), one Bi(3), and four equivalent Bi(4) atoms. All Yb(1)-Sn(1) bond lengths are 3.64 Å. The Yb(1)-Bi(3) bond length is 3.67 Å. All Yb(1)-Bi(4) bond lengths are 3.52 Å. In the second Yb site, Yb(2) is bonded in a 7-coordinate geometry to two equivalent Sn(1), one Bi(1), two equivalent Bi(2), and two equivalent Bi(4) atoms. Both Yb(2)-Sn(1) bond lengths are 3.49 Å. The Yb(2)-Bi(1) bond length is 3.29 Å. Both Yb(2)-Bi(2) bond lengths are 3.25 Å. Both Yb(2)-Bi(4) bond lengths are 3.20 Å. In the third Yb site, Yb(3) is bonded to one Bi(1), one Bi(2), one Bi(3), and four equivalent Bi(4) atoms to form distorted YbBi7 pentagonal bipyramids that share corners with three equivalent Yb(3)Bi7 pentagonal bipyramids, corners with four equivalent Yb(4)SnBi6 pentagonal bipyramids, edges with two equivalent Yb(3)Bi7 pentagonal bipyramids, faces with two equivalent Yb(4)SnBi6 pentagonal bipyramids, and faces with four equivalent Yb(3)Bi7 pentagonal bipyramids. The Yb(3)-Bi(1) bond length is 3.21 Å. The Yb(3)-Bi(2) bond length is 3.55 Å. The Yb(3)-Bi(3) bond length is 3.27 Å. There are two shorter (3.54 Å) and two longer (3.66 Å) Yb(3)-Bi(4) bond lengths. In the fourth Yb site, Yb(4) is bonded to one Sn(1), two equivalent Bi(2), two equivalent Bi(3), and two equivalent Bi(4) atoms to form distorted YbSnBi6 pentagonal bipyramids that share corners with eight equivalent Yb(3)Bi7 pentagonal bipyramids,  an edgeedge with one Yb(4)SnBi6 pentagonal bipyramid, faces with two equivalent Yb(4)SnBi6 pentagonal bipyramids, and faces with four equivalent Yb(3)Bi7 pentagonal bipyramids. The Yb(4)-Sn(1) bond length is 3.51 Å. Both Yb(4)-Bi(2) bond lengths are 3.02 Å. Both Yb(4)-Bi(3) bond lengths are 3.69 Å. Both Yb(4)-Bi(4) bond lengths are 3.69 Å. Sn(1) is bonded in a 11-coordinate geometry to one Yb(4), two equivalent Yb(1), four equivalent Yb(2), two equivalent Sn(1), and two equivalent Bi(4) atoms. Both Sn(1)-Sn(1) bond lengths are 3.02 Å. Both Sn(1)-Bi(4) bond lengths are 3.32 Å. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 8-coordinate geometry to four equivalent Yb(2) and four equivalent Yb(3) atoms. In the second Bi site, Bi(2) is bonded in a 8-coordinate geometry to two equivalent Yb(3), two equivalent Yb(4), and four equivalent Yb(2) atoms. In the third Bi site, Bi(3) is bonded in a 9-coordinate geometry to one Yb(1), four equivalent Yb(3), and four equivalent Yb(4) atoms. In the fourth Bi site, Bi(4) is bonded in a 10-coordinate geometry to one Yb(1), one Yb(4), two equivalent Yb(2), four equivalent Yb(3), one Sn(1), and one Bi(4) atom. The Bi(4)-Bi(4) bond length is 3.20 Å.