Fe2AlBO5 crystallizes in the orthorhombic Pbam space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-70°. In the second Fe site, Fe(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with four equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. In the third Fe site, Fe(3) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form FeO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 17°. Al(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-60°. B(1) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(5) atom. There are five inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Fe(1), one Al(1), and one B(1) atom. In the second O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Fe(2), one Al(1), and one B(1) atom. In the third O site, O(2) is bonded to one Fe(1), one Fe(2), and two equivalent Al(1) atoms to form OAl2Fe2 tetrahedra that share corners with three equivalent O(4)Al2Fe3 square pyramids, corners with three equivalent O(2)Al2Fe2 tetrahedra, and  an edgeedge with one O(4)Al2Fe3 square pyramid. In the fourth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Fe(3), two equivalent Fe(1), and one B(1) atom. In the fifth O site, O(4) is bonded to one Fe(1), two equivalent Fe(3), and two equivalent Al(1) atoms to form OAl2Fe3 square pyramids that share corners with two equivalent O(4)Al2Fe3 square pyramids, corners with three equivalent O(2)Al2Fe2 tetrahedra, edges with three equivalent O(4)Al2Fe3 square pyramids, and  an edgeedge with one O(2)Al2Fe2 tetrahedra.
Fe2AlBO5 crystallizes in the orthorhombic Pbam space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-70°. The Fe(1)-O(2) bond length is 2.02 Å. The Fe(1)-O(4) bond length is 2.12 Å. Both Fe(1)-O(3) bond lengths are 2.20 Å. Both Fe(1)-O(5) bond lengths are 2.22 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with four equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. Both Fe(2)-O(2) bond lengths are 2.08 Å. All Fe(2)-O(1) bond lengths are 2.22 Å. In the third Fe site, Fe(3) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form FeO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 17°. Both Fe(3)-O(3) bond lengths are 2.05 Å. All Fe(3)-O(4) bond lengths are 2.21 Å. Al(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-60°. The Al(1)-O(1) bond length is 2.05 Å. The Al(1)-O(5) bond length is 2.01 Å. Both Al(1)-O(2) bond lengths are 1.93 Å. Both Al(1)-O(4) bond lengths are 1.96 Å. B(1) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(5) atom. The B(1)-O(1) bond length is 1.40 Å. The B(1)-O(3) bond length is 1.38 Å. The B(1)-O(5) bond length is 1.39 Å. There are five inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Fe(1), one Al(1), and one B(1) atom. In the second O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Fe(2), one Al(1), and one B(1) atom. In the third O site, O(2) is bonded to one Fe(1), one Fe(2), and two equivalent Al(1) atoms to form OAl2Fe2 tetrahedra that share corners with three equivalent O(4)Al2Fe3 square pyramids, corners with three equivalent O(2)Al2Fe2 tetrahedra, and  an edgeedge with one O(4)Al2Fe3 square pyramid. In the fourth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Fe(3), two equivalent Fe(1), and one B(1) atom. In the fifth O site, O(4) is bonded to one Fe(1), two equivalent Fe(3), and two equivalent Al(1) atoms to form OAl2Fe3 square pyramids that share corners with two equivalent O(4)Al2Fe3 square pyramids, corners with three equivalent O(2)Al2Fe2 tetrahedra, edges with three equivalent O(4)Al2Fe3 square pyramids, and  an edgeedge with one O(2)Al2Fe2 tetrahedra.