Ba2Co9O14 crystallizes in the trigonal R-3m space group. Ba(1) is bonded in a 9-coordinate geometry to three equivalent O(3) and six equivalent O(1) atoms. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing CoO4 tetrahedra. The corner-sharing octahedral tilt angles range from 22-59°. In the second Co site, Co(2) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form CoO6 octahedra that share corners with three equivalent Co(5)O6 octahedra, corners with three equivalent Co(1)O4 tetrahedra, edges with three equivalent Co(4)O6 octahedra, and  a faceface with one Co(3)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. In the third Co site, Co(3) is bonded to six equivalent O(1) atoms to form CoO6 octahedra that share corners with six equivalent Co(1)O4 tetrahedra and faces with two equivalent Co(2)O6 octahedra. In the fourth Co site, Co(4) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Co(1)O4 tetrahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(5)O6 octahedra, and edges with four equivalent Co(4)O6 octahedra. In the fifth Co site, Co(5) is bonded to six equivalent O(3) atoms to form a mixture of edge and corner-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Co(1), one Co(2), and one Co(3) atom. In the second O site, O(2) is bonded to one Co(1) and three equivalent Co(4) atoms to form distorted corner-sharing OCo4 trigonal pyramids. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Co(2), one Co(5), and two equivalent Co(4) atoms.
Ba2Co9O14 crystallizes in the trigonal R-3m space group. Ba(1) is bonded in a 9-coordinate geometry to three equivalent O(3) and six equivalent O(1) atoms. All Ba(1)-O(3) bond lengths are 2.88 Å. All Ba(1)-O(1) bond lengths are 2.86 Å. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing CoO4 tetrahedra. The corner-sharing octahedral tilt angles range from 22-59°. The Co(1)-O(2) bond length is 1.92 Å. All Co(1)-O(1) bond lengths are 1.92 Å. In the second Co site, Co(2) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form CoO6 octahedra that share corners with three equivalent Co(5)O6 octahedra, corners with three equivalent Co(1)O4 tetrahedra, edges with three equivalent Co(4)O6 octahedra, and  a faceface with one Co(3)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Co(2)-O(1) bond lengths are 1.92 Å. All Co(2)-O(3) bond lengths are 1.94 Å. In the third Co site, Co(3) is bonded to six equivalent O(1) atoms to form CoO6 octahedra that share corners with six equivalent Co(1)O4 tetrahedra and faces with two equivalent Co(2)O6 octahedra. All Co(3)-O(1) bond lengths are 1.95 Å. In the fourth Co site, Co(4) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Co(1)O4 tetrahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(5)O6 octahedra, and edges with four equivalent Co(4)O6 octahedra. Both Co(4)-O(2) bond lengths are 1.92 Å. All Co(4)-O(3) bond lengths are 1.91 Å. In the fifth Co site, Co(5) is bonded to six equivalent O(3) atoms to form a mixture of edge and corner-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Co(5)-O(3) bond lengths are 2.07 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Co(1), one Co(2), and one Co(3) atom. In the second O site, O(2) is bonded to one Co(1) and three equivalent Co(4) atoms to form distorted corner-sharing OCo4 trigonal pyramids. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Co(2), one Co(5), and two equivalent Co(4) atoms.