GdSmB12 is Calcium hexaboride-derived structured and crystallizes in the tetragonal P4/mmm space group. Gd(1) is bonded in a 24-coordinate geometry to eight equivalent B(1) and sixteen equivalent B(2) atoms. Sm(1) is bonded in a 24-coordinate geometry to eight equivalent B(1) and sixteen equivalent B(2) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 5-coordinate geometry to two equivalent Gd(1), two equivalent Sm(1), one B(1), and four equivalent B(2) atoms. In the second B site, B(2) is bonded in a 5-coordinate geometry to two equivalent Gd(1), two equivalent Sm(1), two equivalent B(1), and three equivalent B(2) atoms.
GdSmB12 is Calcium hexaboride-derived structured and crystallizes in the tetragonal P4/mmm space group. Gd(1) is bonded in a 24-coordinate geometry to eight equivalent B(1) and sixteen equivalent B(2) atoms. All Gd(1)-B(1) bond lengths are 3.02 Å. All Gd(1)-B(2) bond lengths are 3.02 Å. Sm(1) is bonded in a 24-coordinate geometry to eight equivalent B(1) and sixteen equivalent B(2) atoms. All Sm(1)-B(1) bond lengths are 3.02 Å. All Sm(1)-B(2) bond lengths are 3.02 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 5-coordinate geometry to two equivalent Gd(1), two equivalent Sm(1), one B(1), and four equivalent B(2) atoms. The B(1)-B(1) bond length is 1.64 Å. All B(1)-B(2) bond lengths are 1.75 Å. In the second B site, B(2) is bonded in a 5-coordinate geometry to two equivalent Gd(1), two equivalent Sm(1), two equivalent B(1), and three equivalent B(2) atoms. There is one shorter (1.64 Å) and two longer (1.75 Å) B(2)-B(2) bond lengths.