KBa3Y2(Co3O8)2 crystallizes in the tetragonal I4mm space group. K(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(5) atoms to form KO12 cuboctahedra that share corners with four equivalent K(1)O12 cuboctahedra, corners with four equivalent Ba(2)O12 cuboctahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(1)O5 trigonal bipyramids. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with four equivalent Ba(3)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with four equivalent K(1)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(1)O5 trigonal bipyramids. In the second Ba site, Ba(2) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent K(1)O12 cuboctahedra, corners with four equivalent Ba(2)O12 cuboctahedra,  a faceface with one Ba(1)O12 cuboctahedra, faces with four equivalent Ba(3)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(2)O5 square pyramids. In the third Ba site, Ba(3) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with four equivalent Ba(3)O12 cuboctahedra,  a faceface with one K(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(2)O5 square pyramids. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a body-centered cubic geometry to four equivalent O(3) and four equivalent O(4) atoms. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to four equivalent O(3) and four equivalent O(4) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1) and four equivalent O(3) atoms to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Co(3)O6 octahedra, corners with four equivalent Co(1)O5 trigonal bipyramids, faces with two equivalent K(1)O12 cuboctahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the second Co site, Co(2) is bonded to one O(2) and four equivalent O(4) atoms to form CoO5 square pyramids that share  a cornercorner with one Co(3)O6 octahedra, corners with four equivalent Co(2)O5 square pyramids, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with two equivalent Ba(3)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the third Co site, Co(3) is bonded to one O(1), one O(2), and four equivalent O(5) atoms to form CoO6 octahedra that share corners with four equivalent Co(3)O6 octahedra,  a cornercorner with one Co(2)O5 square pyramid,  a cornercorner with one Co(1)O5 trigonal bipyramid, faces with two equivalent K(1)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with two equivalent Ba(3)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. There are five inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to one Ba(2), one Ba(3), one Y(1), one Y(2), and two equivalent Co(2) atoms. In the second O site, O(5) is bonded to one K(1), one Ba(1), one Ba(2), one Ba(3), and two equivalent Co(3) atoms to form distorted OKBa3Co2 octahedra that share corners with two equivalent O(5)KBa3Co2 octahedra, corners with four equivalent O(2)Ba4Co2 octahedra, corners with four equivalent O(1)K2Ba2Co2 octahedra, edges with two equivalent O(5)KBa3Co2 octahedra, faces with two equivalent O(2)Ba4Co2 octahedra, faces with two equivalent O(1)K2Ba2Co2 octahedra, and faces with four equivalent O(5)KBa3Co2 octahedra. The corner-sharing octahedral tilt angles range from 3-61°. In the third O site, O(1) is bonded to two equivalent K(1), two equivalent Ba(1), one Co(1), and one Co(3) atom to form distorted OK2Ba2Co2 octahedra that share  a cornercorner with one O(2)Ba4Co2 octahedra, corners with four equivalent O(1)K2Ba2Co2 octahedra, corners with eight equivalent O(5)KBa3Co2 octahedra, edges with four equivalent O(1)K2Ba2Co2 octahedra, and faces with four equivalent O(5)KBa3Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the fourth O site, O(2) is bonded to two equivalent Ba(2), two equivalent Ba(3), one Co(2), and one Co(3) atom to form distorted OBa4Co2 octahedra that share  a cornercorner with one O(1)K2Ba2Co2 octahedra, corners with four equivalent O(2)Ba4Co2 octahedra, corners with eight equivalent O(5)KBa3Co2 octahedra, edges with four equivalent O(2)Ba4Co2 octahedra, and faces with four equivalent O(5)KBa3Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Ba(1), one Y(1), one Y(2), and two equivalent Co(1) atoms.
KBa3Y2(Co3O8)2 crystallizes in the tetragonal I4mm space group. K(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(5) atoms to form KO12 cuboctahedra that share corners with four equivalent K(1)O12 cuboctahedra, corners with four equivalent Ba(2)O12 cuboctahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(1)O5 trigonal bipyramids. All K(1)-O(1) bond lengths are 2.79 Å. All K(1)-O(3) bond lengths are 3.12 Å. All K(1)-O(5) bond lengths are 2.79 Å. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with four equivalent Ba(3)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with four equivalent K(1)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(1)O5 trigonal bipyramids. All Ba(1)-O(1) bond lengths are 2.79 Å. All Ba(1)-O(3) bond lengths are 3.10 Å. All Ba(1)-O(5) bond lengths are 2.76 Å. In the second Ba site, Ba(2) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent K(1)O12 cuboctahedra, corners with four equivalent Ba(2)O12 cuboctahedra,  a faceface with one Ba(1)O12 cuboctahedra, faces with four equivalent Ba(3)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(2)O5 square pyramids. All Ba(2)-O(2) bond lengths are 2.79 Å. All Ba(2)-O(4) bond lengths are 3.08 Å. All Ba(2)-O(5) bond lengths are 2.75 Å. In the third Ba site, Ba(3) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with four equivalent Ba(3)O12 cuboctahedra,  a faceface with one K(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Co(3)O6 octahedra, and faces with four equivalent Co(2)O5 square pyramids. All Ba(3)-O(2) bond lengths are 2.79 Å. All Ba(3)-O(4) bond lengths are 3.13 Å. All Ba(3)-O(5) bond lengths are 2.75 Å. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a body-centered cubic geometry to four equivalent O(3) and four equivalent O(4) atoms. All Y(1)-O(3) bond lengths are 2.40 Å. All Y(1)-O(4) bond lengths are 2.45 Å. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to four equivalent O(3) and four equivalent O(4) atoms. All Y(2)-O(3) bond lengths are 2.40 Å. All Y(2)-O(4) bond lengths are 2.47 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1) and four equivalent O(3) atoms to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Co(3)O6 octahedra, corners with four equivalent Co(1)O5 trigonal bipyramids, faces with two equivalent K(1)O12 cuboctahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Co(1)-O(1) bond length is 1.98 Å. All Co(1)-O(3) bond lengths are 2.03 Å. In the second Co site, Co(2) is bonded to one O(2) and four equivalent O(4) atoms to form CoO5 square pyramids that share  a cornercorner with one Co(3)O6 octahedra, corners with four equivalent Co(2)O5 square pyramids, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with two equivalent Ba(3)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Co(2)-O(2) bond length is 2.08 Å. All Co(2)-O(4) bond lengths are 2.01 Å. In the third Co site, Co(3) is bonded to one O(1), one O(2), and four equivalent O(5) atoms to form CoO6 octahedra that share corners with four equivalent Co(3)O6 octahedra,  a cornercorner with one Co(2)O5 square pyramid,  a cornercorner with one Co(1)O5 trigonal bipyramid, faces with two equivalent K(1)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with two equivalent Ba(3)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. The Co(3)-O(1) bond length is 1.85 Å. The Co(3)-O(2) bond length is 1.91 Å. All Co(3)-O(5) bond lengths are 1.97 Å. There are five inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to one Ba(2), one Ba(3), one Y(1), one Y(2), and two equivalent Co(2) atoms. In the second O site, O(5) is bonded to one K(1), one Ba(1), one Ba(2), one Ba(3), and two equivalent Co(3) atoms to form distorted OKBa3Co2 octahedra that share corners with two equivalent O(5)KBa3Co2 octahedra, corners with four equivalent O(2)Ba4Co2 octahedra, corners with four equivalent O(1)K2Ba2Co2 octahedra, edges with two equivalent O(5)KBa3Co2 octahedra, faces with two equivalent O(2)Ba4Co2 octahedra, faces with two equivalent O(1)K2Ba2Co2 octahedra, and faces with four equivalent O(5)KBa3Co2 octahedra. The corner-sharing octahedral tilt angles range from 3-61°. In the third O site, O(1) is bonded to two equivalent K(1), two equivalent Ba(1), one Co(1), and one Co(3) atom to form distorted OK2Ba2Co2 octahedra that share  a cornercorner with one O(2)Ba4Co2 octahedra, corners with four equivalent O(1)K2Ba2Co2 octahedra, corners with eight equivalent O(5)KBa3Co2 octahedra, edges with four equivalent O(1)K2Ba2Co2 octahedra, and faces with four equivalent O(5)KBa3Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the fourth O site, O(2) is bonded to two equivalent Ba(2), two equivalent Ba(3), one Co(2), and one Co(3) atom to form distorted OBa4Co2 octahedra that share  a cornercorner with one O(1)K2Ba2Co2 octahedra, corners with four equivalent O(2)Ba4Co2 octahedra, corners with eight equivalent O(5)KBa3Co2 octahedra, edges with four equivalent O(2)Ba4Co2 octahedra, and faces with four equivalent O(5)KBa3Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Ba(1), one Y(1), one Y(2), and two equivalent Co(1) atoms.