Ba3TaAs3O crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to one As(1), four equivalent As(2), and one O(1) atom. In the second Ba site, Ba(2) is bonded to two equivalent As(2), three equivalent As(1), and one O(1) atom to form distorted BaAs5O octahedra that share corners with two equivalent Ba(2)As5O octahedra, corners with four equivalent Ta(1)As3O tetrahedra, edges with two equivalent Ba(2)As5O octahedra, and  an edgeedge with one Ta(1)As3O tetrahedra. The corner-sharing octahedral tilt angles are 2°. Ta(1) is bonded to one As(1), two equivalent As(2), and one O(1) atom to form distorted TaAs3O tetrahedra that share corners with four equivalent Ba(2)As5O octahedra and  an edgeedge with one Ba(2)As5O octahedra. The corner-sharing octahedral tilt angles range from 11-81°. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent Ba(1), three equivalent Ba(2), and one Ta(1) atom to form AsBa5Ta octahedra that share corners with two equivalent As(1)Ba5Ta octahedra, corners with four equivalent O(1)Ba3Ta tetrahedra, edges with two equivalent As(1)Ba5Ta octahedra, edges with eight equivalent As(2)Ba5Ta octahedra, and  an edgeedge with one O(1)Ba3Ta tetrahedra. The corner-sharing octahedral tilt angles are 2°. In the second As site, As(2) is bonded to one Ba(2), four equivalent Ba(1), and one Ta(1) atom to form distorted AsBa5Ta octahedra that share corners with six equivalent As(2)Ba5Ta octahedra, corners with two equivalent O(1)Ba3Ta tetrahedra, edges with four equivalent As(1)Ba5Ta octahedra, edges with four equivalent As(2)Ba5Ta octahedra, and edges with two equivalent O(1)Ba3Ta tetrahedra. The corner-sharing octahedral tilt angles range from 6-58°. O(1) is bonded to one Ba(2), two equivalent Ba(1), and one Ta(1) atom to form OBa3Ta tetrahedra that share corners with four equivalent As(1)Ba5Ta octahedra, corners with four equivalent As(2)Ba5Ta octahedra,  an edgeedge with one As(1)Ba5Ta octahedra, and edges with four equivalent As(2)Ba5Ta octahedra. The corner-sharing octahedral tilt angles range from 24-74°.
Ba3TaAs3O crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to one As(1), four equivalent As(2), and one O(1) atom. The Ba(1)-As(1) bond length is 3.31 Å. There are a spread of Ba(1)-As(2) bond distances ranging from 3.36-3.57 Å. The Ba(1)-O(1) bond length is 2.68 Å. In the second Ba site, Ba(2) is bonded to two equivalent As(2), three equivalent As(1), and one O(1) atom to form distorted BaAs5O octahedra that share corners with two equivalent Ba(2)As5O octahedra, corners with four equivalent Ta(1)As3O tetrahedra, edges with two equivalent Ba(2)As5O octahedra, and  an edgeedge with one Ta(1)As3O tetrahedra. The corner-sharing octahedral tilt angles are 2°. Both Ba(2)-As(2) bond lengths are 3.44 Å. There are a spread of Ba(2)-As(1) bond distances ranging from 3.26-3.41 Å. The Ba(2)-O(1) bond length is 2.70 Å. Ta(1) is bonded to one As(1), two equivalent As(2), and one O(1) atom to form distorted TaAs3O tetrahedra that share corners with four equivalent Ba(2)As5O octahedra and  an edgeedge with one Ba(2)As5O octahedra. The corner-sharing octahedral tilt angles range from 11-81°. The Ta(1)-As(1) bond length is 2.47 Å. Both Ta(1)-As(2) bond lengths are 2.47 Å. The Ta(1)-O(1) bond length is 1.87 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent Ba(1), three equivalent Ba(2), and one Ta(1) atom to form AsBa5Ta octahedra that share corners with two equivalent As(1)Ba5Ta octahedra, corners with four equivalent O(1)Ba3Ta tetrahedra, edges with two equivalent As(1)Ba5Ta octahedra, edges with eight equivalent As(2)Ba5Ta octahedra, and  an edgeedge with one O(1)Ba3Ta tetrahedra. The corner-sharing octahedral tilt angles are 2°. In the second As site, As(2) is bonded to one Ba(2), four equivalent Ba(1), and one Ta(1) atom to form distorted AsBa5Ta octahedra that share corners with six equivalent As(2)Ba5Ta octahedra, corners with two equivalent O(1)Ba3Ta tetrahedra, edges with four equivalent As(1)Ba5Ta octahedra, edges with four equivalent As(2)Ba5Ta octahedra, and edges with two equivalent O(1)Ba3Ta tetrahedra. The corner-sharing octahedral tilt angles range from 6-58°. O(1) is bonded to one Ba(2), two equivalent Ba(1), and one Ta(1) atom to form OBa3Ta tetrahedra that share corners with four equivalent As(1)Ba5Ta octahedra, corners with four equivalent As(2)Ba5Ta octahedra,  an edgeedge with one As(1)Ba5Ta octahedra, and edges with four equivalent As(2)Ba5Ta octahedra. The corner-sharing octahedral tilt angles range from 24-74°.