Ba4Ga4SnSe12 crystallizes in the tetragonal P-42_1c space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. Ga(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Sn(1)Se4 tetrahedra and corners with two equivalent Ga(1)Se4 tetrahedra. Sn(1) is bonded to four equivalent Se(1) atoms to form SnSe4 tetrahedra that share corners with four equivalent Ga(1)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(3) is bonded to four equivalent Ba(1) and one Ga(1) atom to form a mixture of distorted corner and edge-sharing SeBa4Ga trigonal bipyramids. In the second Se site, Se(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ga(1), and one Sn(1) atom. In the third Se site, Se(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Ga(1) atoms.
Ba4Ga4SnSe12 crystallizes in the tetragonal P-42_1c space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. There is one shorter (3.48 Å) and one longer (3.74 Å) Ba(1)-Se(1) bond length. Both Ba(1)-Se(2) bond lengths are 3.47 Å. There are a spread of Ba(1)-Se(3) bond distances ranging from 3.36-3.41 Å. Ga(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Sn(1)Se4 tetrahedra and corners with two equivalent Ga(1)Se4 tetrahedra. The Ga(1)-Se(1) bond length is 2.46 Å. The Ga(1)-Se(3) bond length is 2.39 Å. There is one shorter (2.45 Å) and one longer (2.46 Å) Ga(1)-Se(2) bond length. Sn(1) is bonded to four equivalent Se(1) atoms to form SnSe4 tetrahedra that share corners with four equivalent Ga(1)Se4 tetrahedra. All Sn(1)-Se(1) bond lengths are 2.58 Å. There are three inequivalent Se sites. In the first Se site, Se(3) is bonded to four equivalent Ba(1) and one Ga(1) atom to form a mixture of distorted corner and edge-sharing SeBa4Ga trigonal bipyramids. In the second Se site, Se(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ga(1), and one Sn(1) atom. In the third Se site, Se(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Ga(1) atoms.