BaGa2SiSe6 crystallizes in the triclinic P1 space group. Ba(1) is bonded in a 10-coordinate geometry to one Se(1), one Se(4), two equivalent Se(2), two equivalent Se(3), two equivalent Se(5), and two equivalent Se(6) atoms. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(2), one Se(3), one Se(5), and one Se(6) atom to form GaSe4 tetrahedra that share corners with two equivalent Ga(2)Se4 tetrahedra and corners with two equivalent Si(1)Se4 tetrahedra. In the second Ga site, Ga(2) is bonded to one Se(1), one Se(3), one Se(4), and one Se(6) atom to form GaSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra and corners with two equivalent Si(1)Se4 tetrahedra. Si(1) is bonded to one Se(1), one Se(2), one Se(4), and one Se(5) atom to form SiSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra and corners with two equivalent Ga(2)Se4 tetrahedra. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted water-like geometry to one Ba(1), one Ga(2), and one Si(1) atom. In the second Se site, Se(2) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Si(1) atom. In the third Se site, Se(3) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Ga(2) atom. In the fourth Se site, Se(4) is bonded in a distorted water-like geometry to one Ba(1), one Ga(2), and one Si(1) atom. In the fifth Se site, Se(5) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Si(1) atom. In the sixth Se site, Se(6) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Ga(2) atom.
BaGa2SiSe6 crystallizes in the triclinic P1 space group. Ba(1) is bonded in a 10-coordinate geometry to one Se(1), one Se(4), two equivalent Se(2), two equivalent Se(3), two equivalent Se(5), and two equivalent Se(6) atoms. The Ba(1)-Se(1) bond length is 3.53 Å. The Ba(1)-Se(4) bond length is 3.63 Å. There is one shorter (3.61 Å) and one longer (3.76 Å) Ba(1)-Se(2) bond length. There is one shorter (3.54 Å) and one longer (3.81 Å) Ba(1)-Se(3) bond length. There is one shorter (3.71 Å) and one longer (3.86 Å) Ba(1)-Se(5) bond length. There is one shorter (3.64 Å) and one longer (3.85 Å) Ba(1)-Se(6) bond length. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(2), one Se(3), one Se(5), and one Se(6) atom to form GaSe4 tetrahedra that share corners with two equivalent Ga(2)Se4 tetrahedra and corners with two equivalent Si(1)Se4 tetrahedra. The Ga(1)-Se(2) bond length is 2.47 Å. The Ga(1)-Se(3) bond length is 2.41 Å. The Ga(1)-Se(5) bond length is 2.48 Å. The Ga(1)-Se(6) bond length is 2.42 Å. In the second Ga site, Ga(2) is bonded to one Se(1), one Se(3), one Se(4), and one Se(6) atom to form GaSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra and corners with two equivalent Si(1)Se4 tetrahedra. The Ga(2)-Se(1) bond length is 2.46 Å. The Ga(2)-Se(3) bond length is 2.42 Å. The Ga(2)-Se(4) bond length is 2.48 Å. The Ga(2)-Se(6) bond length is 2.42 Å. Si(1) is bonded to one Se(1), one Se(2), one Se(4), and one Se(5) atom to form SiSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra and corners with two equivalent Ga(2)Se4 tetrahedra. The Si(1)-Se(1) bond length is 2.30 Å. The Si(1)-Se(2) bond length is 2.29 Å. The Si(1)-Se(4) bond length is 2.30 Å. The Si(1)-Se(5) bond length is 2.31 Å. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted water-like geometry to one Ba(1), one Ga(2), and one Si(1) atom. In the second Se site, Se(2) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Si(1) atom. In the third Se site, Se(3) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Ga(2) atom. In the fourth Se site, Se(4) is bonded in a distorted water-like geometry to one Ba(1), one Ga(2), and one Si(1) atom. In the fifth Se site, Se(5) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Si(1) atom. In the sixth Se site, Se(6) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ga(1), and one Ga(2) atom.