SB12 crystallizes in the trigonal R3m space group. There are four inequivalent B sites. In the first B site, B(1) is bonded in a 6-coordinate geometry to one B(2), one B(3), two equivalent B(1), and two equivalent B(4) atoms. In the second B site, B(2) is bonded in a 6-coordinate geometry to one B(1), one B(4), two equivalent B(2), and two equivalent B(3) atoms. In the third B site, B(3) is bonded in a 5-coordinate geometry to one B(1), two equivalent B(2), and two equivalent B(4) atoms. In the fourth B site, B(4) is bonded in a distorted single-bond geometry to one B(2), two equivalent B(1), two equivalent B(3), and one S(1) atom. S(1) is bonded in a trigonal non-coplanar geometry to three equivalent B(4) atoms.
SB12 crystallizes in the trigonal R3m space group. There are four inequivalent B sites. In the first B site, B(1) is bonded in a 6-coordinate geometry to one B(2), one B(3), two equivalent B(1), and two equivalent B(4) atoms. The B(1)-B(2) bond length is 1.73 Å. The B(1)-B(3) bond length is 1.82 Å. Both B(1)-B(1) bond lengths are 1.81 Å. Both B(1)-B(4) bond lengths are 1.75 Å. In the second B site, B(2) is bonded in a 6-coordinate geometry to one B(1), one B(4), two equivalent B(2), and two equivalent B(3) atoms. The B(2)-B(4) bond length is 1.79 Å. Both B(2)-B(2) bond lengths are 1.84 Å. Both B(2)-B(3) bond lengths are 1.83 Å. In the third B site, B(3) is bonded in a 5-coordinate geometry to one B(1), two equivalent B(2), and two equivalent B(4) atoms. Both B(3)-B(4) bond lengths are 1.74 Å. In the fourth B site, B(4) is bonded in a distorted single-bond geometry to one B(2), two equivalent B(1), two equivalent B(3), and one S(1) atom. The B(4)-S(1) bond length is 1.80 Å. S(1) is bonded in a trigonal non-coplanar geometry to three equivalent B(4) atoms.