Ba2Ti2AlF11 crystallizes in the trigonal P3_2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 12-coordinate geometry to one F(1), one F(10), one F(11), one F(2), one F(3), one F(6), one F(7), one F(8), two equivalent F(4), and two equivalent F(5) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one F(1), one F(11), one F(3), one F(4), one F(5), one F(7), one F(9), two equivalent F(2), and two equivalent F(8) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one F(1), one F(2), one F(3), one F(4), one F(6), and one F(9) atom. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one F(1), one F(10), one F(11), one F(6), one F(8), and one F(9) atom. Al(1) is bonded in an octahedral geometry to one F(10), one F(11), one F(3), one F(5), one F(7), and one F(9) atom. There are eleven inequivalent F sites. In the first F site, F(10) is bonded in a distorted water-like geometry to one Ba(1), one Ti(2), and one Al(1) atom. In the second F site, F(11) is bonded in a 1-coordinate geometry to one Ba(1), one Ba(2), one Ti(2), and one Al(1) atom. In the third F site, F(1) is bonded to one Ba(1), one Ba(2), one Ti(1), and one Ti(2) atom to form distorted edge-sharing FBa2Ti2 tetrahedra. In the fourth F site, F(2) is bonded in a distorted single-bond geometry to one Ba(1), two equivalent Ba(2), and one Ti(1) atom. In the fifth F site, F(3) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ti(1), and one Al(1) atom. In the sixth F site, F(4) is bonded to one Ba(2), two equivalent Ba(1), and one Ti(1) atom to form distorted FBa3Ti tetrahedra that share corners with two equivalent F(4)Ba3Ti tetrahedra and edges with two equivalent F(1)Ba2Ti2 tetrahedra. In the seventh F site, F(5) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one Al(1) atom. In the eighth F site, F(6) is bonded in a 3-coordinate geometry to one Ba(1), one Ti(1), and one Ti(2) atom. In the ninth F site, F(7) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one Al(1) atom. In the tenth F site, F(8) is bonded in a 3-coordinate geometry to one Ba(1), two equivalent Ba(2), and one Ti(2) atom. In the eleventh F site, F(9) is bonded in a 4-coordinate geometry to one Ba(2), one Ti(1), one Ti(2), and one Al(1) atom.
Ba2Ti2AlF11 crystallizes in the trigonal P3_2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 12-coordinate geometry to one F(1), one F(10), one F(11), one F(2), one F(3), one F(6), one F(7), one F(8), two equivalent F(4), and two equivalent F(5) atoms. The Ba(1)-F(1) bond length is 2.88 Å. The Ba(1)-F(10) bond length is 3.07 Å. The Ba(1)-F(11) bond length is 2.80 Å. The Ba(1)-F(2) bond length is 2.91 Å. The Ba(1)-F(3) bond length is 3.03 Å. The Ba(1)-F(6) bond length is 2.66 Å. The Ba(1)-F(7) bond length is 3.23 Å. The Ba(1)-F(8) bond length is 2.68 Å. There is one shorter (2.88 Å) and one longer (2.93 Å) Ba(1)-F(4) bond length. There is one shorter (2.73 Å) and one longer (3.13 Å) Ba(1)-F(5) bond length. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one F(1), one F(11), one F(3), one F(4), one F(5), one F(7), one F(9), two equivalent F(2), and two equivalent F(8) atoms. The Ba(2)-F(1) bond length is 2.89 Å. The Ba(2)-F(11) bond length is 3.15 Å. The Ba(2)-F(3) bond length is 2.73 Å. The Ba(2)-F(4) bond length is 2.77 Å. The Ba(2)-F(5) bond length is 2.87 Å. The Ba(2)-F(7) bond length is 2.62 Å. The Ba(2)-F(9) bond length is 3.06 Å. There is one shorter (2.88 Å) and one longer (3.17 Å) Ba(2)-F(2) bond length. There is one shorter (2.80 Å) and one longer (3.30 Å) Ba(2)-F(8) bond length. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one F(1), one F(2), one F(3), one F(4), one F(6), and one F(9) atom. The Ti(1)-F(1) bond length is 2.21 Å. The Ti(1)-F(2) bond length is 1.98 Å. The Ti(1)-F(3) bond length is 2.25 Å. The Ti(1)-F(4) bond length is 2.05 Å. The Ti(1)-F(6) bond length is 2.07 Å. The Ti(1)-F(9) bond length is 2.21 Å. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one F(1), one F(10), one F(11), one F(6), one F(8), and one F(9) atom. The Ti(2)-F(1) bond length is 2.12 Å. The Ti(2)-F(10) bond length is 2.13 Å. The Ti(2)-F(11) bond length is 2.32 Å. The Ti(2)-F(6) bond length is 2.00 Å. The Ti(2)-F(8) bond length is 2.06 Å. The Ti(2)-F(9) bond length is 2.42 Å. Al(1) is bonded in an octahedral geometry to one F(10), one F(11), one F(3), one F(5), one F(7), and one F(9) atom. The Al(1)-F(10) bond length is 1.84 Å. The Al(1)-F(11) bond length is 1.84 Å. The Al(1)-F(3) bond length is 1.87 Å. The Al(1)-F(5) bond length is 1.81 Å. The Al(1)-F(7) bond length is 1.76 Å. The Al(1)-F(9) bond length is 1.91 Å. There are eleven inequivalent F sites. In the first F site, F(10) is bonded in a distorted water-like geometry to one Ba(1), one Ti(2), and one Al(1) atom. In the second F site, F(11) is bonded in a 1-coordinate geometry to one Ba(1), one Ba(2), one Ti(2), and one Al(1) atom. In the third F site, F(1) is bonded to one Ba(1), one Ba(2), one Ti(1), and one Ti(2) atom to form distorted edge-sharing FBa2Ti2 tetrahedra. In the fourth F site, F(2) is bonded in a distorted single-bond geometry to one Ba(1), two equivalent Ba(2), and one Ti(1) atom. In the fifth F site, F(3) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ti(1), and one Al(1) atom. In the sixth F site, F(4) is bonded to one Ba(2), two equivalent Ba(1), and one Ti(1) atom to form distorted FBa3Ti tetrahedra that share corners with two equivalent F(4)Ba3Ti tetrahedra and edges with two equivalent F(1)Ba2Ti2 tetrahedra. In the seventh F site, F(5) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one Al(1) atom. In the eighth F site, F(6) is bonded in a 3-coordinate geometry to one Ba(1), one Ti(1), and one Ti(2) atom. In the ninth F site, F(7) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one Al(1) atom. In the tenth F site, F(8) is bonded in a 3-coordinate geometry to one Ba(1), two equivalent Ba(2), and one Ti(2) atom. In the eleventh F site, F(9) is bonded in a 4-coordinate geometry to one Ba(2), one Ti(1), one Ti(2), and one Al(1) atom.