VAl2O7 crystallizes in the monoclinic C2/m space group. V(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form VO4 tetrahedra that share corners with two equivalent Al(2)O4 tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. In the second Al site, Al(2) is bonded to one O(1), one O(2), and two equivalent O(5) atoms to form AlO4 tetrahedra that share corners with two equivalent V(1)O4 tetrahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one V(1) and one Al(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one V(1) and one Al(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one V(1) and one Al(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to two equivalent Al(1) atoms. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Al(1) and one Al(2) atom.
VAl2O7 crystallizes in the monoclinic C2/m space group. V(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form VO4 tetrahedra that share corners with two equivalent Al(2)O4 tetrahedra. The V(1)-O(1) bond length is 1.74 Å. The V(1)-O(2) bond length is 1.75 Å. Both V(1)-O(3) bond lengths are 1.73 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. Both Al(1)-O(3) bond lengths are 1.81 Å. Both Al(1)-O(4) bond lengths are 2.07 Å. Both Al(1)-O(5) bond lengths are 1.84 Å. In the second Al site, Al(2) is bonded to one O(1), one O(2), and two equivalent O(5) atoms to form AlO4 tetrahedra that share corners with two equivalent V(1)O4 tetrahedra. The Al(2)-O(1) bond length is 1.76 Å. The Al(2)-O(2) bond length is 1.76 Å. Both Al(2)-O(5) bond lengths are 1.78 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one V(1) and one Al(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one V(1) and one Al(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one V(1) and one Al(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to two equivalent Al(1) atoms. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Al(1) and one Al(2) atom.