Ba2YCo2TlO7 crystallizes in the monoclinic Pm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(5), one O(6), one O(7), one O(8), two equivalent O(3), and two equivalent O(4) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(2), one O(5), one O(6), one O(7), one O(8), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a body-centered cubic geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO5 square pyramids that share corners with four equivalent Co(2)O5 square pyramids and  a cornercorner with one Tl(2)O4 trigonal pyramid. In the second Co site, Co(2) is bonded to one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO5 square pyramids that share corners with four equivalent Co(1)O5 square pyramids and  a cornercorner with one Tl(1)O4 trigonal pyramid. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form TlO4 trigonal pyramids that share corners with two equivalent Co(2)O5 square pyramids and corners with two equivalent Tl(2)O4 trigonal pyramids. In the second Tl site, Tl(2) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form TlO4 trigonal pyramids that share corners with two equivalent Co(1)O5 square pyramids and corners with two equivalent Tl(1)O4 trigonal pyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to two equivalent Ba(1), one Tl(1), and one Tl(2) atom. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ba(2), one Tl(1), and one Tl(2) atom. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(2), and one Tl(1) atom to form a mixture of distorted corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles are 20°. In the fourth O site, O(4) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(1), and one Tl(2) atom to form a mixture of distorted corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles range from 19-21°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom.
Ba2YCo2TlO7 crystallizes in the monoclinic Pm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(5), one O(6), one O(7), one O(8), two equivalent O(3), and two equivalent O(4) atoms. The Ba(1)-O(1) bond length is 2.67 Å. The Ba(1)-O(5) bond length is 3.00 Å. The Ba(1)-O(6) bond length is 2.99 Å. The Ba(1)-O(7) bond length is 3.00 Å. The Ba(1)-O(8) bond length is 2.99 Å. There is one shorter (2.79 Å) and one longer (2.87 Å) Ba(1)-O(3) bond length. There is one shorter (2.79 Å) and one longer (2.94 Å) Ba(1)-O(4) bond length. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(2), one O(5), one O(6), one O(7), one O(8), two equivalent O(3), and two equivalent O(4) atoms. The Ba(2)-O(2) bond length is 2.67 Å. The Ba(2)-O(5) bond length is 3.00 Å. The Ba(2)-O(6) bond length is 2.99 Å. The Ba(2)-O(7) bond length is 3.00 Å. The Ba(2)-O(8) bond length is 2.99 Å. There is one shorter (2.79 Å) and one longer (2.94 Å) Ba(2)-O(3) bond length. There is one shorter (2.79 Å) and one longer (2.87 Å) Ba(2)-O(4) bond length. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a body-centered cubic geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. Both Y(1)-O(5) bond lengths are 2.45 Å. Both Y(1)-O(6) bond lengths are 2.45 Å. Both Y(1)-O(7) bond lengths are 2.45 Å. Both Y(1)-O(8) bond lengths are 2.44 Å. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. Both Y(2)-O(5) bond lengths are 2.45 Å. Both Y(2)-O(6) bond lengths are 2.44 Å. Both Y(2)-O(7) bond lengths are 2.45 Å. Both Y(2)-O(8) bond lengths are 2.45 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO5 square pyramids that share corners with four equivalent Co(2)O5 square pyramids and  a cornercorner with one Tl(2)O4 trigonal pyramid. The Co(1)-O(4) bond length is 2.55 Å. The Co(1)-O(5) bond length is 1.99 Å. The Co(1)-O(6) bond length is 2.00 Å. The Co(1)-O(7) bond length is 1.99 Å. The Co(1)-O(8) bond length is 1.99 Å. In the second Co site, Co(2) is bonded to one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO5 square pyramids that share corners with four equivalent Co(1)O5 square pyramids and  a cornercorner with one Tl(1)O4 trigonal pyramid. The Co(2)-O(3) bond length is 2.52 Å. The Co(2)-O(5) bond length is 2.00 Å. The Co(2)-O(6) bond length is 2.00 Å. The Co(2)-O(7) bond length is 1.99 Å. The Co(2)-O(8) bond length is 1.99 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form TlO4 trigonal pyramids that share corners with two equivalent Co(2)O5 square pyramids and corners with two equivalent Tl(2)O4 trigonal pyramids. The Tl(1)-O(1) bond length is 2.30 Å. The Tl(1)-O(2) bond length is 2.30 Å. Both Tl(1)-O(3) bond lengths are 2.17 Å. In the second Tl site, Tl(2) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form TlO4 trigonal pyramids that share corners with two equivalent Co(1)O5 square pyramids and corners with two equivalent Tl(1)O4 trigonal pyramids. The Tl(2)-O(1) bond length is 2.32 Å. The Tl(2)-O(2) bond length is 2.31 Å. Both Tl(2)-O(4) bond lengths are 2.15 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to two equivalent Ba(1), one Tl(1), and one Tl(2) atom. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ba(2), one Tl(1), and one Tl(2) atom. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(2), and one Tl(1) atom to form a mixture of distorted corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles are 20°. In the fourth O site, O(4) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Co(1), and one Tl(2) atom to form a mixture of distorted corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles range from 19-21°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Y(1), one Y(2), one Co(1), and one Co(2) atom.