BaAl2O8 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to one O(1), one O(5), one O(7), one O(8), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted edge-sharing AlO6 octahedra. In the second Al site, Al(2) is bonded to one O(1), one O(5), one O(7), one O(8), and two equivalent O(6) atoms to form edge-sharing AlO6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Ba(1) and one Al(2) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Ba(1) and one Al(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Al(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and one Al(1) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Ba(1), one Al(1), and one Al(2) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Al(1) and two equivalent Al(2) atoms. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1) and one Al(2) atom. In the eighth O site, O(8) is bonded in a distorted L-shaped geometry to one Ba(1), one Al(1), and one Al(2) atom.
BaAl2O8 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to one O(1), one O(5), one O(7), one O(8), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ba(1)-O(1) bond length is 2.75 Å. The Ba(1)-O(5) bond length is 3.00 Å. The Ba(1)-O(7) bond length is 2.82 Å. The Ba(1)-O(8) bond length is 2.77 Å. There is one shorter (2.81 Å) and one longer (3.15 Å) Ba(1)-O(2) bond length. There is one shorter (2.81 Å) and one longer (3.11 Å) Ba(1)-O(3) bond length. There is one shorter (2.77 Å) and one longer (2.83 Å) Ba(1)-O(4) bond length. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted edge-sharing AlO6 octahedra. The Al(1)-O(2) bond length is 2.01 Å. The Al(1)-O(3) bond length is 1.86 Å. The Al(1)-O(4) bond length is 1.82 Å. The Al(1)-O(5) bond length is 1.86 Å. The Al(1)-O(6) bond length is 1.93 Å. The Al(1)-O(8) bond length is 1.84 Å. In the second Al site, Al(2) is bonded to one O(1), one O(5), one O(7), one O(8), and two equivalent O(6) atoms to form edge-sharing AlO6 octahedra. The Al(2)-O(1) bond length is 1.85 Å. The Al(2)-O(5) bond length is 1.89 Å. The Al(2)-O(7) bond length is 1.86 Å. The Al(2)-O(8) bond length is 1.90 Å. There is one shorter (1.91 Å) and one longer (1.95 Å) Al(2)-O(6) bond length. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Ba(1) and one Al(2) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Ba(1) and one Al(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Al(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and one Al(1) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Ba(1), one Al(1), and one Al(2) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Al(1) and two equivalent Al(2) atoms. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1) and one Al(2) atom. In the eighth O site, O(8) is bonded in a distorted L-shaped geometry to one Ba(1), one Al(1), and one Al(2) atom.