BaAl2O6 crystallizes in the orthorhombic Pna2_1 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(2), one O(5), one O(6), two equivalent O(1), 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(1), one O(2), and two equivalent O(3) atoms to form AlO4 tetrahedra that share  a cornercorner with one Al(2)O5 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(1), one O(4), one O(6), and two equivalent O(5) atoms to form AlO5 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra and corners with two equivalent Al(2)O5 tetrahedra. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted single-bond geometry to one Ba(1) and one Al(2) atom. In the second O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Al(1), and one Al(2) atom. In the third O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ba(1) and one Al(1) atom. In the fourth O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Al(1) atoms. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and one Al(2) atom. In the sixth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ba(1) and two equivalent Al(2) atoms.
BaAl2O6 crystallizes in the orthorhombic Pna2_1 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(2), one O(5), one O(6), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. The Ba(1)-O(2) bond length is 2.69 Å. The Ba(1)-O(5) bond length is 2.83 Å. The Ba(1)-O(6) bond length is 2.70 Å. There is one shorter (2.99 Å) and one longer (3.11 Å) Ba(1)-O(1) bond length. There is one shorter (2.80 Å) and one longer (2.94 Å) Ba(1)-O(3) bond length. There is one shorter (3.05 Å) and one longer (3.16 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(1), one O(2), and two equivalent O(3) atoms to form AlO4 tetrahedra that share  a cornercorner with one Al(2)O5 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. The Al(1)-O(1) bond length is 1.77 Å. The Al(1)-O(2) bond length is 1.79 Å. Both Al(1)-O(3) bond lengths are 1.75 Å. In the second Al site, Al(2) is bonded to one O(1), one O(4), one O(6), and two equivalent O(5) atoms to form AlO5 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra and corners with two equivalent Al(2)O5 tetrahedra. The Al(2)-O(1) bond length is 1.75 Å. The Al(2)-O(4) bond length is 2.46 Å. The Al(2)-O(6) bond length is 1.81 Å. There is one shorter (1.78 Å) and one longer (1.79 Å) Al(2)-O(5) bond length. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted single-bond geometry to one Ba(1) and one Al(2) atom. In the second O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Al(1), and one Al(2) atom. In the third O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ba(1) and one Al(1) atom. In the fourth O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Al(1) atoms. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and one Al(2) atom. In the sixth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ba(1) and two equivalent Al(2) atoms.