Ba2Co2TlAlO7 crystallizes in the triclinic P1 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(5), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(4), two equivalent O(6), and four equivalent O(7) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. In the second Co site, Co(2) is bonded in a 6-coordinate geometry to one O(3), one O(7), two equivalent O(4), and two equivalent O(6) atoms. Tl(1) is bonded in a see-saw-like geometry to one O(1), one O(7), and two equivalent O(5) atoms. Al(1) is bonded in a distorted trigonal pyramidal geometry to one O(2), one O(3), one O(4), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Co(1), and one Tl(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Co(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Ba(1), one Co(2), two equivalent Co(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(2), one Co(1), two equivalent Co(2), and one Al(1) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Tl(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Ba(2), two equivalent Co(2), and one Al(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to four equivalent Ba(2), one Co(2), and one Tl(1) atom.
Ba2Co2TlAlO7 crystallizes in the triclinic P1 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(5), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. The Ba(1)-O(5) bond length is 2.63 Å. There is one shorter (2.71 Å) and one longer (2.82 Å) Ba(1)-O(2) bond length. There is one shorter (2.84 Å) and one longer (3.24 Å) Ba(1)-O(3) bond length. There are a spread of Ba(1)-O(1) bond distances ranging from 2.81-3.12 Å. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(4), two equivalent O(6), and four equivalent O(7) atoms. The Ba(2)-O(5) bond length is 2.66 Å. There is one shorter (2.82 Å) and one longer (3.16 Å) Ba(2)-O(4) bond length. There is one shorter (2.73 Å) and one longer (2.83 Å) Ba(2)-O(6) bond length. There are a spread of Ba(2)-O(7) bond distances ranging from 2.83-3.13 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. The Co(1)-O(1) bond length is 2.15 Å. The Co(1)-O(4) bond length is 2.58 Å. There is one shorter (1.98 Å) and one longer (2.33 Å) Co(1)-O(2) bond length. There is one shorter (2.03 Å) and one longer (2.17 Å) Co(1)-O(3) bond length. In the second Co site, Co(2) is bonded in a 6-coordinate geometry to one O(3), one O(7), two equivalent O(4), and two equivalent O(6) atoms. The Co(2)-O(3) bond length is 2.43 Å. The Co(2)-O(7) bond length is 2.28 Å. There is one shorter (2.00 Å) and one longer (2.16 Å) Co(2)-O(4) bond length. There is one shorter (1.97 Å) and one longer (2.32 Å) Co(2)-O(6) bond length. Tl(1) is bonded in a see-saw-like geometry to one O(1), one O(7), and two equivalent O(5) atoms. The Tl(1)-O(1) bond length is 2.17 Å. The Tl(1)-O(7) bond length is 2.15 Å. Both Tl(1)-O(5) bond lengths are 2.32 Å. Al(1) is bonded in a distorted trigonal pyramidal geometry to one O(2), one O(3), one O(4), and one O(6) atom. The Al(1)-O(2) bond length is 1.77 Å. The Al(1)-O(3) bond length is 1.83 Å. The Al(1)-O(4) bond length is 1.83 Å. The Al(1)-O(6) bond length is 1.77 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Co(1), and one Tl(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Co(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Ba(1), one Co(2), two equivalent Co(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(2), one Co(1), two equivalent Co(2), and one Al(1) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Tl(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Ba(2), two equivalent Co(2), and one Al(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to four equivalent Ba(2), one Co(2), and one Tl(1) atom.