Ba2Fe2TlAlO7 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 Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing FeO5 square pyramids. In the second Fe site, Fe(2) is bonded to one O(7), two equivalent O(4), and two equivalent O(6) atoms to form distorted corner-sharing FeO5 square pyramids. 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 square co-planar 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 to four equivalent Ba(1), one Fe(1), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 17-19°. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), two equivalent Fe(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), two equivalent Fe(2), and one Al(1) atom. In the fifth O site, O(5) is bonded in a 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 Fe(2), and one Al(1) atom. In the seventh O site, O(7) is bonded to four equivalent Ba(2), one Fe(2), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 15-19°.
Ba2Fe2TlAlO7 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 2.65 Å. There is one shorter (2.86 Å) and one longer (3.04 Å) Ba(1)-O(2) bond length. There is one shorter (2.87 Å) and one longer (3.07 Å) Ba(1)-O(3) bond length. There are a spread of Ba(1)-O(1) bond distances ranging from 2.79-3.00 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 2.63 Å. There is one shorter (2.86 Å) and one longer (3.06 Å) Ba(2)-O(4) bond length. There is one shorter (2.86 Å) and one longer (3.04 Å) Ba(2)-O(6) bond length. There are a spread of Ba(2)-O(7) bond distances ranging from 2.79-3.11 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing FeO5 square pyramids. The Fe(1)-O(1) bond length is 2.37 Å. There is one shorter (2.01 Å) and one longer (2.14 Å) Fe(1)-O(2) bond length. There is one shorter (1.99 Å) and one longer (2.09 Å) Fe(1)-O(3) bond length. In the second Fe site, Fe(2) is bonded to one O(7), two equivalent O(4), and two equivalent O(6) atoms to form distorted corner-sharing FeO5 square pyramids. The Fe(2)-O(7) bond length is 2.29 Å. There is one shorter (2.00 Å) and one longer (2.10 Å) Fe(2)-O(4) bond length. There is one shorter (2.01 Å) and one longer (2.15 Å) Fe(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 2.18 Å. The Tl(1)-O(7) bond length is 2.20 Å. There is one shorter (2.34 Å) and one longer (2.37 Å) Tl(1)-O(5) bond length. Al(1) is bonded in a square co-planar geometry to one O(2), one O(3), one O(4), and one O(6) atom. The Al(1)-O(2) bond length is 1.86 Å. The Al(1)-O(3) bond length is 1.86 Å. The Al(1)-O(4) bond length is 1.86 Å. The Al(1)-O(6) bond length is 1.87 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Fe(1), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 17-19°. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), two equivalent Fe(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), two equivalent Fe(2), and one Al(1) atom. In the fifth O site, O(5) is bonded in a 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 Fe(2), and one Al(1) atom. In the seventh O site, O(7) is bonded to four equivalent Ba(2), one Fe(2), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 15-19°.