BaAl2O6 crystallizes in the monoclinic C2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(5), and four equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(6), and four 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), one O(3), and one O(5) atom to form corner-sharing AlO4 tetrahedra. In the second Al site, Al(2) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form corner-sharing AlO4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ba(2), one Al(1), and one Al(2) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ba(2), one Al(1), and one Al(2) 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 distorted single-bond geometry to two equivalent Ba(2) and one Al(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Ba(1) and one Al(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ba(2) and one Al(2) atom.
BaAl2O6 crystallizes in the monoclinic C2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(5), and four equivalent O(3) atoms. Both Ba(1)-O(1) bond lengths are 3.21 Å. Both Ba(1)-O(2) bond lengths are 2.84 Å. Both Ba(1)-O(5) bond lengths are 2.74 Å. There are two shorter (2.84 Å) and two longer (3.09 Å) Ba(1)-O(3) bond lengths. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(6), and four equivalent O(4) atoms. Both Ba(2)-O(1) bond lengths are 2.83 Å. Both Ba(2)-O(2) bond lengths are 3.21 Å. Both Ba(2)-O(6) bond lengths are 2.75 Å. There are two shorter (2.81 Å) and two longer (3.12 Å) Ba(2)-O(4) bond lengths. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form corner-sharing AlO4 tetrahedra. The Al(1)-O(1) bond length is 1.74 Å. The Al(1)-O(2) bond length is 1.73 Å. The Al(1)-O(3) bond length is 1.80 Å. The Al(1)-O(5) bond length is 1.81 Å. In the second Al site, Al(2) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form corner-sharing AlO4 tetrahedra. The Al(2)-O(1) bond length is 1.74 Å. The Al(2)-O(2) bond length is 1.74 Å. The Al(2)-O(4) bond length is 1.79 Å. The Al(2)-O(6) bond length is 1.81 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ba(2), one Al(1), and one Al(2) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ba(2), one Al(1), and one Al(2) 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 distorted single-bond geometry to two equivalent Ba(2) and one Al(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Ba(1) and one Al(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ba(2) and one Al(2) atom.