BaAl2B2O7 crystallizes in the trigonal R32 space group. Ba(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. Al(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing AlO4 tetrahedra. B(1) is bonded in a trigonal planar geometry to three equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Al(1), and one B(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Al(1) atoms.
BaAl2B2O7 crystallizes in the trigonal R32 space group. Ba(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. All Ba(1)-O(1) bond lengths are 2.78 Å. Al(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing AlO4 tetrahedra. The Al(1)-O(2) bond length is 1.69 Å. All Al(1)-O(1) bond lengths are 1.79 Å. B(1) is bonded in a trigonal planar geometry to three equivalent O(1) atoms. All B(1)-O(1) bond lengths are 1.38 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Al(1), and one B(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Al(1) atoms.