Ba2YCo2TlO7 crystallizes in the triclinic P1 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(7), two equivalent O(9), and four equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(10), two equivalent O(8), and four equivalent O(4) atoms. In the third Ba site, Ba(3) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(11), two equivalent O(13), and four equivalent O(5) atoms. In the fourth Ba site, Ba(4) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(12), two equivalent O(14), and four equivalent O(6) 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(11), two equivalent O(13), two equivalent O(7), and two equivalent O(9) atoms. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to two equivalent O(10), two equivalent O(12), two equivalent O(14), and two equivalent O(8) atoms. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(4), two equivalent O(10), and two equivalent O(8) atoms to form distorted corner-sharing CoO5 trigonal bipyramids. In the second Co site, Co(2) is bonded to one O(6), two equivalent O(12), and two equivalent O(14) atoms to form corner-sharing CoO5 square pyramids. In the third Co site, Co(3) is bonded to one O(3), two equivalent O(7), and two equivalent O(9) atoms to form corner-sharing CoO5 square pyramids. In the fourth Co site, Co(4) is bonded to one O(5), two equivalent O(11), and two equivalent O(13) atoms to form distorted corner-sharing CoO5 trigonal bipyramids. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a see-saw-like geometry to one O(3), one O(6), and two equivalent O(1) atoms. In the second Tl site, Tl(2) is bonded in a 5-coordinate geometry to one O(4), one O(5), and three equivalent O(2) atoms. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Ba(1), one Ba(4), and two equivalent Tl(1) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), and three equivalent Tl(2) atoms. In the third O site, O(3) is bonded to four equivalent Ba(1), one Co(3), and one Tl(1) atom to form distorted OBa4TlCo octahedra that share  a cornercorner with one O(6)Ba4TlCo octahedra, corners with four equivalent O(7)Ba2Y2Co2 octahedra, corners with four equivalent O(3)Ba4TlCo octahedra, edges with four equivalent O(3)Ba4TlCo octahedra, and faces with two equivalent O(7)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 18-55°. In the fourth O site, O(4) is bonded to four equivalent Ba(2), one Co(1), and one Tl(2) atom to form a mixture of corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles are 4°. In the fifth O site, O(5) is bonded to four equivalent Ba(3), one Co(4), and one Tl(2) atom to form a mixture of corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles range from 4-5°. In the sixth O site, O(6) is bonded to four equivalent Ba(4), one Co(2), and one Tl(1) atom to form distorted OBa4TlCo octahedra that share  a cornercorner with one O(3)Ba4TlCo octahedra, corners with four equivalent O(14)Ba2Y2Co2 octahedra, corners with four equivalent O(6)Ba4TlCo octahedra, edges with four equivalent O(6)Ba4TlCo octahedra, and faces with two equivalent O(14)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 18-55°. In the seventh O site, O(7) is bonded to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(3) atoms to form distorted OBa2Y2Co2 octahedra that share corners with two equivalent O(7)Ba2Y2Co2 octahedra, corners with four equivalent O(3)Ba4TlCo octahedra, edges with two equivalent O(7)Ba2Y2Co2 octahedra, and faces with two equivalent O(3)Ba4TlCo octahedra. The corner-sharing octahedral tilt angles range from 12-55°. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Y(2), and two equivalent Co(1) atoms. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(3) atoms. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Y(2), and two equivalent Co(1) atoms. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to two equivalent Ba(3), two equivalent Y(1), and two equivalent Co(4) atoms. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to two equivalent Ba(4), two equivalent Y(2), and two equivalent Co(2) atoms. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to two equivalent Ba(3), two equivalent Y(1), and two equivalent Co(4) atoms. In the fourteenth O site, O(14) is bonded to two equivalent Ba(4), two equivalent Y(2), and two equivalent Co(2) atoms to form distorted OBa2Y2Co2 octahedra that share corners with two equivalent O(14)Ba2Y2Co2 octahedra, corners with four equivalent O(6)Ba4TlCo octahedra, edges with two equivalent O(14)Ba2Y2Co2 octahedra, and faces with two equivalent O(6)Ba4TlCo octahedra. The corner-sharing octahedral tilt angles range from 13-55°.
Ba2YCo2TlO7 crystallizes in the triclinic P1 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(7), two equivalent O(9), and four equivalent O(3) atoms. The Ba(1)-O(1) bond length is 2.67 Å. There is one shorter (2.93 Å) and one longer (2.94 Å) Ba(1)-O(7) bond length. There is one shorter (2.94 Å) and one longer (2.95 Å) Ba(1)-O(9) bond length. There are a spread of Ba(1)-O(3) bond distances ranging from 2.79-2.89 Å. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(10), two equivalent O(8), and four equivalent O(4) atoms. The Ba(2)-O(2) bond length is 2.68 Å. Both Ba(2)-O(10) bond lengths are 3.10 Å. There is one shorter (3.09 Å) and one longer (3.10 Å) Ba(2)-O(8) bond length. There are a spread of Ba(2)-O(4) bond distances ranging from 2.78-2.82 Å. In the third Ba site, Ba(3) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(11), two equivalent O(13), and four equivalent O(5) atoms. The Ba(3)-O(2) bond length is 2.68 Å. Both Ba(3)-O(11) bond lengths are 3.08 Å. Both Ba(3)-O(13) bond lengths are 3.07 Å. There are a spread of Ba(3)-O(5) bond distances ranging from 2.78-2.81 Å. In the fourth Ba site, Ba(4) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(12), two equivalent O(14), and four equivalent O(6) atoms. The Ba(4)-O(1) bond length is 2.66 Å. There is one shorter (2.93 Å) and one longer (2.94 Å) Ba(4)-O(12) bond length. There is one shorter (2.92 Å) and one longer (2.93 Å) Ba(4)-O(14) bond length. There are a spread of Ba(4)-O(6) bond distances ranging from 2.78-2.88 Å. 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(11), two equivalent O(13), two equivalent O(7), and two equivalent O(9) atoms. Both Y(1)-O(11) bond lengths are 2.38 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) Y(1)-O(13) bond length. Both Y(1)-O(7) bond lengths are 2.50 Å. There is one shorter (2.50 Å) and one longer (2.51 Å) Y(1)-O(9) bond length. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to two equivalent O(10), two equivalent O(12), two equivalent O(14), and two equivalent O(8) atoms. Both Y(2)-O(10) bond lengths are 2.38 Å. There is one shorter (2.50 Å) and one longer (2.51 Å) Y(2)-O(12) bond length. Both Y(2)-O(14) bond lengths are 2.50 Å. Both Y(2)-O(8) bond lengths are 2.37 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(4), two equivalent O(10), and two equivalent O(8) atoms to form distorted corner-sharing CoO5 trigonal bipyramids. The Co(1)-O(4) bond length is 2.04 Å. There is one shorter (2.01 Å) and one longer (2.03 Å) Co(1)-O(10) bond length. Both Co(1)-O(8) bond lengths are 2.03 Å. In the second Co site, Co(2) is bonded to one O(6), two equivalent O(12), and two equivalent O(14) atoms to form corner-sharing CoO5 square pyramids. The Co(2)-O(6) bond length is 2.40 Å. There is one shorter (1.97 Å) and one longer (1.99 Å) Co(2)-O(12) bond length. There is one shorter (1.98 Å) and one longer (2.00 Å) Co(2)-O(14) bond length. In the third Co site, Co(3) is bonded to one O(3), two equivalent O(7), and two equivalent O(9) atoms to form corner-sharing CoO5 square pyramids. The Co(3)-O(3) bond length is 2.46 Å. Both Co(3)-O(7) bond lengths are 1.99 Å. Both Co(3)-O(9) bond lengths are 1.98 Å. In the fourth Co site, Co(4) is bonded to one O(5), two equivalent O(11), and two equivalent O(13) atoms to form distorted corner-sharing CoO5 trigonal bipyramids. The Co(4)-O(5) bond length is 2.04 Å. Both Co(4)-O(11) bond lengths are 2.02 Å. There is one shorter (2.02 Å) and one longer (2.03 Å) Co(4)-O(13) bond length. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a see-saw-like geometry to one O(3), one O(6), and two equivalent O(1) atoms. The Tl(1)-O(3) bond length is 2.17 Å. The Tl(1)-O(6) bond length is 2.17 Å. There is one shorter (2.34 Å) and one longer (2.35 Å) Tl(1)-O(1) bond length. In the second Tl site, Tl(2) is bonded in a 5-coordinate geometry to one O(4), one O(5), and three equivalent O(2) atoms. The Tl(2)-O(4) bond length is 2.55 Å. The Tl(2)-O(5) bond length is 2.53 Å. There are a spread of Tl(2)-O(2) bond distances ranging from 2.35-2.85 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Ba(1), one Ba(4), and two equivalent Tl(1) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), and three equivalent Tl(2) atoms. In the third O site, O(3) is bonded to four equivalent Ba(1), one Co(3), and one Tl(1) atom to form distorted OBa4TlCo octahedra that share  a cornercorner with one O(6)Ba4TlCo octahedra, corners with four equivalent O(7)Ba2Y2Co2 octahedra, corners with four equivalent O(3)Ba4TlCo octahedra, edges with four equivalent O(3)Ba4TlCo octahedra, and faces with two equivalent O(7)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 18-55°. In the fourth O site, O(4) is bonded to four equivalent Ba(2), one Co(1), and one Tl(2) atom to form a mixture of corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles are 4°. In the fifth O site, O(5) is bonded to four equivalent Ba(3), one Co(4), and one Tl(2) atom to form a mixture of corner and edge-sharing OBa4TlCo octahedra. The corner-sharing octahedral tilt angles range from 4-5°. In the sixth O site, O(6) is bonded to four equivalent Ba(4), one Co(2), and one Tl(1) atom to form distorted OBa4TlCo octahedra that share  a cornercorner with one O(3)Ba4TlCo octahedra, corners with four equivalent O(14)Ba2Y2Co2 octahedra, corners with four equivalent O(6)Ba4TlCo octahedra, edges with four equivalent O(6)Ba4TlCo octahedra, and faces with two equivalent O(14)Ba2Y2Co2 octahedra. The corner-sharing octahedral tilt angles range from 18-55°. In the seventh O site, O(7) is bonded to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(3) atoms to form distorted OBa2Y2Co2 octahedra that share corners with two equivalent O(7)Ba2Y2Co2 octahedra, corners with four equivalent O(3)Ba4TlCo octahedra, edges with two equivalent O(7)Ba2Y2Co2 octahedra, and faces with two equivalent O(3)Ba4TlCo octahedra. The corner-sharing octahedral tilt angles range from 12-55°. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Y(2), and two equivalent Co(1) atoms. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Co(3) atoms. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent Ba(2), two equivalent Y(2), and two equivalent Co(1) atoms. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to two equivalent Ba(3), two equivalent Y(1), and two equivalent Co(4) atoms. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to two equivalent Ba(4), two equivalent Y(2), and two equivalent Co(2) atoms. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to two equivalent Ba(3), two equivalent Y(1), and two equivalent Co(4) atoms. In the fourteenth O site, O(14) is bonded to two equivalent Ba(4), two equivalent Y(2), and two equivalent Co(2) atoms to form distorted OBa2Y2Co2 octahedra that share corners with two equivalent O(14)Ba2Y2Co2 octahedra, corners with four equivalent O(6)Ba4TlCo octahedra, edges with two equivalent O(14)Ba2Y2Co2 octahedra, and faces with two equivalent O(6)Ba4TlCo octahedra. The corner-sharing octahedral tilt angles range from 13-55°.