Sr8Co8O23 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 11-coordinate geometry to one O(4), two equivalent O(3), four equivalent O(1), and four equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded to one O(4), one O(5), two equivalent O(3), four equivalent O(1), and four equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with six equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Co(2)O6 octahedra, faces with four equivalent Co(1)O6 octahedra, and faces with two equivalent Co(3)O5 square pyramids. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Co(1)O6 octahedra; corners with two Co(2,2)O6 octahedra; corners with two equivalent Co(3)O5 square pyramids; and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the second Co site, Co(2) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the third Co site, Co(3) is bonded to one O(5) and four equivalent O(2) atoms to form CoO5 square pyramids that share corners with four equivalent Co(1)O6 octahedra,  a cornercorner with one Co(3)O5 square pyramid, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 12°. In the fourth Co site, Co(2) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), one Co(1), and one Co(2) atom to form a mixture of distorted edge, face, and corner-sharing OSr4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), one Co(1), and one Co(3) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Co(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Co(2) atoms to form a mixture of distorted face and corner-sharing OSr4Co2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to four equivalent Sr(2) and two equivalent Co(3) atoms to form corner-sharing OSr4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°.
Sr8Co8O23 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 11-coordinate geometry to one O(4), two equivalent O(3), four equivalent O(1), and four equivalent O(2) atoms. The Sr(1)-O(4) bond length is 2.65 Å. Both Sr(1)-O(3) bond lengths are 2.93 Å. All Sr(1)-O(1) bond lengths are 2.70 Å. All Sr(1)-O(2) bond lengths are 2.63 Å. In the second Sr site, Sr(2) is bonded to one O(4), one O(5), two equivalent O(3), four equivalent O(1), and four equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with six equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Co(2)O6 octahedra, faces with four equivalent Co(1)O6 octahedra, and faces with two equivalent Co(3)O5 square pyramids. The Sr(2)-O(4) bond length is 2.80 Å. The Sr(2)-O(5) bond length is 2.69 Å. Both Sr(2)-O(3) bond lengths are 2.57 Å. All Sr(2)-O(1) bond lengths are 2.77 Å. All Sr(2)-O(2) bond lengths are 2.90 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Co(1)O6 octahedra; corners with two Co(2,2)O6 octahedra; corners with two equivalent Co(3)O5 square pyramids; and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-15°. Both Co(1)-O(1) bond lengths are 1.86 Å. Both Co(1)-O(2) bond lengths are 2.09 Å. Both Co(1)-O(3) bond lengths are 1.95 Å. In the second Co site, Co(2) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. Both Co(2)-O(4) bond lengths are 1.94 Å. All Co(2)-O(1) bond lengths are 2.03 Å. In the third Co site, Co(3) is bonded to one O(5) and four equivalent O(2) atoms to form CoO5 square pyramids that share corners with four equivalent Co(1)O6 octahedra,  a cornercorner with one Co(3)O5 square pyramid, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 12°. The Co(3)-O(5) bond length is 2.01 Å. All Co(3)-O(2) bond lengths are 1.82 Å. In the fourth Co site, Co(2) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. Both Co(2)-O(4) bond lengths are 1.94 Å. All Co(2)-O(1) bond lengths are 2.03 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), one Co(1), and one Co(2) atom to form a mixture of distorted edge, face, and corner-sharing OSr4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), one Co(1), and one Co(3) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Co(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Co(2) atoms to form a mixture of distorted face and corner-sharing OSr4Co2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to four equivalent Sr(2) and two equivalent Co(3) atoms to form corner-sharing OSr4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°.