YBaCo2O5 crystallizes in the orthorhombic Pmm2 space group. Ba(1) is bonded to one O(2), one O(3), one O(6), one O(7), two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(8) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Co(2)O5 square pyramids, faces with two equivalent Co(1)O5 trigonal bipyramids, faces with two equivalent Co(3)O5 trigonal bipyramids, and faces with two equivalent Co(4)O5 trigonal bipyramids. Y(1) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(6), one O(7), two equivalent O(1), and two equivalent O(5) atoms. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(8), two equivalent O(5), and two equivalent O(6) atoms to form CoO5 trigonal bipyramids that share corners with two equivalent Co(2)O5 square pyramids,  a cornercorner with one Co(3)O5 trigonal bipyramid, corners with two equivalent Co(1)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. In the second Co site, Co(2) is bonded to one O(4), two equivalent O(2), and two equivalent O(5) atoms to form CoO5 square pyramids that share corners with two equivalent Co(2)O5 square pyramids,  a cornercorner with one Co(4)O5 trigonal bipyramid, corners with two equivalent Co(1)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. In the third Co site, Co(3) is bonded to one O(8), two equivalent O(1), and two equivalent O(7) atoms to form CoO5 trigonal bipyramids that share  a cornercorner with one Co(1)O5 trigonal bipyramid, corners with two equivalent Co(3)O5 trigonal bipyramids, corners with two equivalent Co(4)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. In the fourth Co site, Co(4) is bonded to one O(4), two equivalent O(1), and two equivalent O(3) atoms to form CoO5 trigonal bipyramids that share  a cornercorner with one Co(2)O5 square pyramid, corners with two equivalent Co(3)O5 trigonal bipyramids, corners with two equivalent Co(4)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), one Co(3), and one Co(4) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(2) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(4) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Co(2), and one Co(4) atom to form a mixture of corner and edge-sharing OBa4Co2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), one Co(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(1) atoms. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(3) atoms. In the eighth O site, O(8) is bonded to four equivalent Ba(1), one Co(1), and one Co(3) atom to form a mixture of corner and edge-sharing OBa4Co2 octahedra. The corner-sharing octahedra are not tilted.
YBaCo2O5 crystallizes in the orthorhombic Pmm2 space group. Ba(1) is bonded to one O(2), one O(3), one O(6), one O(7), two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(8) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Co(2)O5 square pyramids, faces with two equivalent Co(1)O5 trigonal bipyramids, faces with two equivalent Co(3)O5 trigonal bipyramids, and faces with two equivalent Co(4)O5 trigonal bipyramids. The Ba(1)-O(2) bond length is 2.99 Å. The Ba(1)-O(3) bond length is 2.98 Å. The Ba(1)-O(6) bond length is 3.01 Å. The Ba(1)-O(7) bond length is 2.99 Å. Both Ba(1)-O(1) bond lengths are 3.09 Å. Both Ba(1)-O(4) bond lengths are 2.73 Å. Both Ba(1)-O(5) bond lengths are 3.08 Å. Both Ba(1)-O(8) bond lengths are 2.75 Å. Y(1) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(6), one O(7), two equivalent O(1), and two equivalent O(5) atoms. The Y(1)-O(2) bond length is 2.43 Å. The Y(1)-O(3) bond length is 2.44 Å. The Y(1)-O(6) bond length is 2.40 Å. The Y(1)-O(7) bond length is 2.42 Å. Both Y(1)-O(1) bond lengths are 2.39 Å. Both Y(1)-O(5) bond lengths are 2.39 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(8), two equivalent O(5), and two equivalent O(6) atoms to form CoO5 trigonal bipyramids that share corners with two equivalent Co(2)O5 square pyramids,  a cornercorner with one Co(3)O5 trigonal bipyramid, corners with two equivalent Co(1)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The Co(1)-O(8) bond length is 1.97 Å. Both Co(1)-O(5) bond lengths are 1.93 Å. Both Co(1)-O(6) bond lengths are 1.98 Å. In the second Co site, Co(2) is bonded to one O(4), two equivalent O(2), and two equivalent O(5) atoms to form CoO5 square pyramids that share corners with two equivalent Co(2)O5 square pyramids,  a cornercorner with one Co(4)O5 trigonal bipyramid, corners with two equivalent Co(1)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The Co(2)-O(4) bond length is 2.00 Å. Both Co(2)-O(2) bond lengths are 1.97 Å. Both Co(2)-O(5) bond lengths are 1.99 Å. In the third Co site, Co(3) is bonded to one O(8), two equivalent O(1), and two equivalent O(7) atoms to form CoO5 trigonal bipyramids that share  a cornercorner with one Co(1)O5 trigonal bipyramid, corners with two equivalent Co(3)O5 trigonal bipyramids, corners with two equivalent Co(4)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The Co(3)-O(8) bond length is 1.97 Å. Both Co(3)-O(1) bond lengths are 1.97 Å. Both Co(3)-O(7) bond lengths are 1.98 Å. In the fourth Co site, Co(4) is bonded to one O(4), two equivalent O(1), and two equivalent O(3) atoms to form CoO5 trigonal bipyramids that share  a cornercorner with one Co(2)O5 square pyramid, corners with two equivalent Co(3)O5 trigonal bipyramids, corners with two equivalent Co(4)O5 trigonal bipyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The Co(4)-O(4) bond length is 1.99 Å. Both Co(4)-O(1) bond lengths are 1.97 Å. Both Co(4)-O(3) bond lengths are 1.97 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), one Co(3), and one Co(4) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(2) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(4) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Co(2), and one Co(4) atom to form a mixture of corner and edge-sharing OBa4Co2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), one Co(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(1) atoms. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(3) atoms. In the eighth O site, O(8) is bonded to four equivalent Ba(1), one Co(1), and one Co(3) atom to form a mixture of corner and edge-sharing OBa4Co2 octahedra. The corner-sharing octahedra are not tilted.