GaAlO3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(2), one O(5), and two equivalent O(1) atoms to form GaO4 tetrahedra that share  a cornercorner with one Al(2)O6 octahedra, corners with three equivalent Ga(2)O6 octahedra, and corners with two equivalent Ga(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-73°. In the second Ga site, Ga(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form GaO6 octahedra that share corners with two equivalent Al(2)O6 octahedra, corners with three equivalent Ga(1)O4 tetrahedra, edges with two equivalent Ga(2)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-51°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the second Al site, Al(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with two equivalent Ga(2)O6 octahedra,  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Ga(2)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-51°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Ga(1) and one Al(1) atom. In the second O site, O(2) is bonded to one Ga(1), one Ga(2), one Al(1), and one Al(2) atom to form OAl2Ga2 tetrahedra that share  a cornercorner with one O(3)Al3Ga2 square pyramid, corners with two equivalent O(5)AlGa3 tetrahedra, edges with two equivalent O(3)Al3Ga2 square pyramids, and  an edgeedge with one O(5)AlGa3 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ga(2), one Al(1), and two equivalent Al(2) atoms to form distorted OAl3Ga2 square pyramids that share  a cornercorner with one O(2)Al2Ga2 tetrahedra,  a cornercorner with one O(5)AlGa3 tetrahedra, edges with two equivalent O(3)Al3Ga2 square pyramids, edges with two equivalent O(2)Al2Ga2 tetrahedra, and edges with two equivalent O(5)AlGa3 tetrahedra. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Al(1) and two equivalent Al(2) atoms. In the fifth O site, O(5) is bonded to one Ga(1), two equivalent Ga(2), and one Al(1) atom to form OAlGa3 tetrahedra that share  a cornercorner with one O(3)Al3Ga2 square pyramid, corners with two equivalent O(2)Al2Ga2 tetrahedra, corners with two equivalent O(5)AlGa3 tetrahedra, edges with two equivalent O(3)Al3Ga2 square pyramids, and  an edgeedge with one O(2)Al2Ga2 tetrahedra. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ga(2), one Al(1), and one Al(2) atom.
GaAlO3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(2), one O(5), and two equivalent O(1) atoms to form GaO4 tetrahedra that share  a cornercorner with one Al(2)O6 octahedra, corners with three equivalent Ga(2)O6 octahedra, and corners with two equivalent Ga(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-73°. The Ga(1)-O(2) bond length is 1.86 Å. The Ga(1)-O(5) bond length is 1.88 Å. There is one shorter (1.83 Å) and one longer (1.86 Å) Ga(1)-O(1) bond length. In the second Ga site, Ga(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form GaO6 octahedra that share corners with two equivalent Al(2)O6 octahedra, corners with three equivalent Ga(1)O4 tetrahedra, edges with two equivalent Ga(2)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-51°. The Ga(2)-O(2) bond length is 2.04 Å. The Ga(2)-O(6) bond length is 1.91 Å. There is one shorter (2.01 Å) and one longer (2.04 Å) Ga(2)-O(3) bond length. Both Ga(2)-O(5) bond lengths are 2.04 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Al(1)-O(1) bond length is 1.87 Å. The Al(1)-O(2) bond length is 1.96 Å. The Al(1)-O(3) bond length is 2.40 Å. The Al(1)-O(4) bond length is 1.82 Å. The Al(1)-O(5) bond length is 1.98 Å. The Al(1)-O(6) bond length is 1.85 Å. In the second Al site, Al(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with two equivalent Ga(2)O6 octahedra,  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Ga(2)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-51°. The Al(2)-O(2) bond length is 2.02 Å. The Al(2)-O(6) bond length is 1.86 Å. There is one shorter (2.01 Å) and one longer (2.23 Å) Al(2)-O(3) bond length. There is one shorter (1.86 Å) and one longer (1.87 Å) Al(2)-O(4) bond length. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Ga(1) and one Al(1) atom. In the second O site, O(2) is bonded to one Ga(1), one Ga(2), one Al(1), and one Al(2) atom to form OAl2Ga2 tetrahedra that share  a cornercorner with one O(3)Al3Ga2 square pyramid, corners with two equivalent O(5)AlGa3 tetrahedra, edges with two equivalent O(3)Al3Ga2 square pyramids, and  an edgeedge with one O(5)AlGa3 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ga(2), one Al(1), and two equivalent Al(2) atoms to form distorted OAl3Ga2 square pyramids that share  a cornercorner with one O(2)Al2Ga2 tetrahedra,  a cornercorner with one O(5)AlGa3 tetrahedra, edges with two equivalent O(3)Al3Ga2 square pyramids, edges with two equivalent O(2)Al2Ga2 tetrahedra, and edges with two equivalent O(5)AlGa3 tetrahedra. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Al(1) and two equivalent Al(2) atoms. In the fifth O site, O(5) is bonded to one Ga(1), two equivalent Ga(2), and one Al(1) atom to form OAlGa3 tetrahedra that share  a cornercorner with one O(3)Al3Ga2 square pyramid, corners with two equivalent O(2)Al2Ga2 tetrahedra, corners with two equivalent O(5)AlGa3 tetrahedra, edges with two equivalent O(3)Al3Ga2 square pyramids, and  an edgeedge with one O(2)Al2Ga2 tetrahedra. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ga(2), one Al(1), and one Al(2) atom.