Ba3(OCl)2 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 4-coordinate geometry to four equivalent O(1) and one Cl(1) atom. In the second Ba site, Ba(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1), one Cl(1), and one Cl(2) atom. In the third Ba site, Ba(3) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent Cl(2), and three equivalent Cl(1) atoms. O(1) is bonded to one Ba(2), one Ba(3), and two equivalent Ba(1) atoms to form OBa4 tetrahedra that share corners with four equivalent Cl(1)Ba5 square pyramids, corners with two equivalent O(1)Ba4 tetrahedra,  an edgeedge with one Cl(1)Ba5 square pyramid, and edges with three equivalent O(1)Ba4 tetrahedra. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to one Ba(1), one Ba(2), and three equivalent Ba(3) atoms to form distorted ClBa5 square pyramids that share corners with two equivalent Cl(1)Ba5 square pyramids, corners with eight equivalent O(1)Ba4 tetrahedra, edges with two equivalent Cl(1)Ba5 square pyramids, and edges with two equivalent O(1)Ba4 tetrahedra. In the second Cl site, Cl(2) is bonded in a 3-coordinate geometry to one Ba(2) and two equivalent Ba(3) atoms.
Ba3(OCl)2 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 4-coordinate geometry to four equivalent O(1) and one Cl(1) atom. There are two shorter (2.59 Å) and two longer (2.61 Å) Ba(1)-O(1) bond lengths. The Ba(1)-Cl(1) bond length is 3.46 Å. In the second Ba site, Ba(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1), one Cl(1), and one Cl(2) atom. Both Ba(2)-O(1) bond lengths are 2.41 Å. The Ba(2)-Cl(1) bond length is 3.27 Å. The Ba(2)-Cl(2) bond length is 3.22 Å. In the third Ba site, Ba(3) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent Cl(2), and three equivalent Cl(1) atoms. Both Ba(3)-O(1) bond lengths are 2.48 Å. There is one shorter (3.33 Å) and one longer (3.47 Å) Ba(3)-Cl(2) bond length. There is one shorter (3.40 Å) and two longer (3.58 Å) Ba(3)-Cl(1) bond lengths. O(1) is bonded to one Ba(2), one Ba(3), and two equivalent Ba(1) atoms to form OBa4 tetrahedra that share corners with four equivalent Cl(1)Ba5 square pyramids, corners with two equivalent O(1)Ba4 tetrahedra,  an edgeedge with one Cl(1)Ba5 square pyramid, and edges with three equivalent O(1)Ba4 tetrahedra. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to one Ba(1), one Ba(2), and three equivalent Ba(3) atoms to form distorted ClBa5 square pyramids that share corners with two equivalent Cl(1)Ba5 square pyramids, corners with eight equivalent O(1)Ba4 tetrahedra, edges with two equivalent Cl(1)Ba5 square pyramids, and edges with two equivalent O(1)Ba4 tetrahedra. In the second Cl site, Cl(2) is bonded in a 3-coordinate geometry to one Ba(2) and two equivalent Ba(3) atoms.