Sr3TaAs3O crystallizes in the orthorhombic Pnma space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one As(1), four equivalent As(2), and one O(1) atom. In the second Sr site, Sr(2) is bonded to two equivalent As(2), three equivalent As(1), and one O(1) atom to form distorted SrAs5O octahedra that share corners with two equivalent Sr(2)As5O octahedra, corners with four equivalent Ta(1)As3O tetrahedra, edges with two equivalent Sr(2)As5O octahedra, and  an edgeedge with one Ta(1)As3O tetrahedra. The corner-sharing octahedral tilt angles are 4°. 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 Sr(2)As5O octahedra and  an edgeedge with one Sr(2)As5O octahedra. The corner-sharing octahedral tilt angles range from 12-80°. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Ta(1) atom to form AsSr5Ta octahedra that share corners with two equivalent As(1)Sr5Ta octahedra, corners with four equivalent O(1)Sr3Ta tetrahedra, edges with two equivalent As(1)Sr5Ta octahedra, edges with eight equivalent As(2)Sr5Ta octahedra, and  an edgeedge with one O(1)Sr3Ta tetrahedra. The corner-sharing octahedral tilt angles are 4°. In the second As site, As(2) is bonded to one Sr(2), four equivalent Sr(1), and one Ta(1) atom to form distorted AsSr5Ta octahedra that share corners with six equivalent As(2)Sr5Ta octahedra, corners with two equivalent O(1)Sr3Ta tetrahedra, edges with four equivalent As(1)Sr5Ta octahedra, edges with four equivalent As(2)Sr5Ta octahedra, and edges with two equivalent O(1)Sr3Ta tetrahedra. The corner-sharing octahedral tilt angles range from 3-58°. O(1) is bonded to one Sr(2), two equivalent Sr(1), and one Ta(1) atom to form OSr3Ta tetrahedra that share corners with four equivalent As(1)Sr5Ta octahedra, corners with four equivalent As(2)Sr5Ta octahedra,  an edgeedge with one As(1)Sr5Ta octahedra, and edges with four equivalent As(2)Sr5Ta octahedra. The corner-sharing octahedral tilt angles range from 20-75°.
Sr3TaAs3O crystallizes in the orthorhombic Pnma space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one As(1), four equivalent As(2), and one O(1) atom. The Sr(1)-As(1) bond length is 3.16 Å. There are a spread of Sr(1)-As(2) bond distances ranging from 3.17-3.44 Å. The Sr(1)-O(1) bond length is 2.53 Å. In the second Sr site, Sr(2) is bonded to two equivalent As(2), three equivalent As(1), and one O(1) atom to form distorted SrAs5O octahedra that share corners with two equivalent Sr(2)As5O octahedra, corners with four equivalent Ta(1)As3O tetrahedra, edges with two equivalent Sr(2)As5O octahedra, and  an edgeedge with one Ta(1)As3O tetrahedra. The corner-sharing octahedral tilt angles are 4°. Both Sr(2)-As(2) bond lengths are 3.22 Å. There are a spread of Sr(2)-As(1) bond distances ranging from 3.07-3.25 Å. The Sr(2)-O(1) bond length is 2.55 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 Sr(2)As5O octahedra and  an edgeedge with one Sr(2)As5O octahedra. The corner-sharing octahedral tilt angles range from 12-80°. The Ta(1)-As(1) bond length is 2.47 Å. Both Ta(1)-As(2) bond lengths are 2.48 Å. The Ta(1)-O(1) bond length is 1.89 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Ta(1) atom to form AsSr5Ta octahedra that share corners with two equivalent As(1)Sr5Ta octahedra, corners with four equivalent O(1)Sr3Ta tetrahedra, edges with two equivalent As(1)Sr5Ta octahedra, edges with eight equivalent As(2)Sr5Ta octahedra, and  an edgeedge with one O(1)Sr3Ta tetrahedra. The corner-sharing octahedral tilt angles are 4°. In the second As site, As(2) is bonded to one Sr(2), four equivalent Sr(1), and one Ta(1) atom to form distorted AsSr5Ta octahedra that share corners with six equivalent As(2)Sr5Ta octahedra, corners with two equivalent O(1)Sr3Ta tetrahedra, edges with four equivalent As(1)Sr5Ta octahedra, edges with four equivalent As(2)Sr5Ta octahedra, and edges with two equivalent O(1)Sr3Ta tetrahedra. The corner-sharing octahedral tilt angles range from 3-58°. O(1) is bonded to one Sr(2), two equivalent Sr(1), and one Ta(1) atom to form OSr3Ta tetrahedra that share corners with four equivalent As(1)Sr5Ta octahedra, corners with four equivalent As(2)Sr5Ta octahedra,  an edgeedge with one As(1)Sr5Ta octahedra, and edges with four equivalent As(2)Sr5Ta octahedra. The corner-sharing octahedral tilt angles range from 20-75°.