AlNbO4 crystallizes in the monoclinic C2/m space group. Nb(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. Al(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 24°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Nb(1) and one Al(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Nb(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Nb(1) and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded in a linear geometry to one Nb(1) and one Al(1) atom.
AlNbO4 crystallizes in the monoclinic C2/m space group. Nb(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. The Nb(1)-O(2) bond length is 2.03 Å. The Nb(1)-O(3) bond length is 1.95 Å. The Nb(1)-O(4) bond length is 1.81 Å. Both Nb(1)-O(1) bond lengths are 2.01 Å. Al(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 24°. The Al(1)-O(1) bond length is 2.01 Å. The Al(1)-O(4) bond length is 1.89 Å. Both Al(1)-O(2) bond lengths are 1.95 Å. There is one shorter (1.86 Å) and one longer (1.96 Å) Al(1)-O(3) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Nb(1) and one Al(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Nb(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Nb(1) and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded in a linear geometry to one Nb(1) and one Al(1) atom.