NaTi2Al5O12 crystallizes in the orthorhombic Pbam space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(3) and four equivalent O(5) atoms. Ti(1) is bonded to one O(1), one O(6), two equivalent O(4), and two equivalent O(5) atoms to form distorted TiO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Al(3)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form AlO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra, corners with four equivalent Al(3)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. In the second Al site, Al(2) is bonded to one O(4), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form AlO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Al(3)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the third Al site, Al(3) is bonded to one O(3), one O(6), and two equivalent O(2) atoms to form AlO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with four equivalent Al(2)O6 octahedra, and corners with two equivalent Al(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-67°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ti(1) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Al(1) and two equivalent Al(3) atoms. In the third O site, O(3) is bonded to one Na(1), one Al(3), and two equivalent Al(2) atoms to form distorted ONaAl3 tetrahedra that share corners with two equivalent O(5)Na2Ti2Al square pyramids, corners with three equivalent O(3)NaAl3 tetrahedra, and edges with two equivalent O(5)Na2Ti2Al square pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one Al(2) atom. In the fifth O site, O(5) is bonded to two equivalent Na(1), two equivalent Ti(1), and one Al(2) atom to form distorted ONa2Ti2Al square pyramids that share corners with two equivalent O(5)Na2Ti2Al square pyramids, corners with two equivalent O(3)NaAl3 tetrahedra, edges with three equivalent O(5)Na2Ti2Al square pyramids, and edges with two equivalent O(3)NaAl3 tetrahedra. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Ti(1), one Al(3), and two equivalent Al(2) atoms.
NaTi2Al5O12 crystallizes in the orthorhombic Pbam space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(3) and four equivalent O(5) atoms. Both Na(1)-O(3) bond lengths are 2.50 Å. All Na(1)-O(5) bond lengths are 2.47 Å. Ti(1) is bonded to one O(1), one O(6), two equivalent O(4), and two equivalent O(5) atoms to form distorted TiO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Al(3)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. The Ti(1)-O(1) bond length is 1.82 Å. The Ti(1)-O(6) bond length is 2.17 Å. Both Ti(1)-O(4) bond lengths are 1.93 Å. Both Ti(1)-O(5) bond lengths are 2.00 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form AlO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra, corners with four equivalent Al(3)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. Both Al(1)-O(2) bond lengths are 1.87 Å. All Al(1)-O(1) bond lengths are 1.92 Å. In the second Al site, Al(2) is bonded to one O(4), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form AlO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Al(3)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. The Al(2)-O(4) bond length is 1.87 Å. The Al(2)-O(5) bond length is 1.94 Å. Both Al(2)-O(3) bond lengths are 1.90 Å. Both Al(2)-O(6) bond lengths are 1.96 Å. In the third Al site, Al(3) is bonded to one O(3), one O(6), and two equivalent O(2) atoms to form AlO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with four equivalent Al(2)O6 octahedra, and corners with two equivalent Al(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-67°. The Al(3)-O(3) bond length is 1.77 Å. The Al(3)-O(6) bond length is 1.79 Å. Both Al(3)-O(2) bond lengths are 1.74 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ti(1) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Al(1) and two equivalent Al(3) atoms. In the third O site, O(3) is bonded to one Na(1), one Al(3), and two equivalent Al(2) atoms to form distorted ONaAl3 tetrahedra that share corners with two equivalent O(5)Na2Ti2Al square pyramids, corners with three equivalent O(3)NaAl3 tetrahedra, and edges with two equivalent O(5)Na2Ti2Al square pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one Al(2) atom. In the fifth O site, O(5) is bonded to two equivalent Na(1), two equivalent Ti(1), and one Al(2) atom to form distorted ONa2Ti2Al square pyramids that share corners with two equivalent O(5)Na2Ti2Al square pyramids, corners with two equivalent O(3)NaAl3 tetrahedra, edges with three equivalent O(5)Na2Ti2Al square pyramids, and edges with two equivalent O(3)NaAl3 tetrahedra. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Ti(1), one Al(3), and two equivalent Al(2) atoms.