The compound described by Ti7Al2O15 crystallizes in the monoclinic C2/m space group. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(7), two equivalent O(5), and two equivalent O(8) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Al(1)O4 tetrahedra, and edges with three equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. In the second Ti site, Ti(2) is bonded to one O(6), two equivalent O(7), and three equivalent O(1) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with three equivalent Al(1)O4 tetrahedra, and edges with four equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. In the third Ti site, Ti(3) is bonded to one O(4), two equivalent O(6), and three equivalent O(3) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with three equivalent Al(1)O4 tetrahedra, and edges with four equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the fourth Ti site, Ti(4) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 49°. Al(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra, and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Ti(2) and one Al(1) atom to form a mixture of distorted corner and edge-sharing OTi3Al tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ti(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded to three equivalent Ti(3) and one Al(1) atom to form a mixture of distorted corner and edge-sharing OTi3Al tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(4) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(4) and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ti(2) and two equivalent Ti(3) atoms. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Ti(1) and two equivalent Ti(2) atoms. In the eighth O site, O(8) is bonded in a square co-planar geometry to four equivalent Ti(1) atoms. is represented by the CIF card [CIF]
data_Ti7Al2O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.157
_cell_length_b   9.157
_cell_length_c   9.454
_cell_angle_alpha   81.567
_cell_angle_beta   81.567
_cell_angle_gamma   18.678
_symmetry_Int_Tables_number   1
_cell_volume   251.019
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ti  Ti0  1  0.509  0.509  0.649  1.0
  Ti  Ti1  1  0.491  0.491  0.351  1.0
  Ti  Ti2  1  0.189  0.189  0.615  1.0
  Ti  Ti3  1  0.811  0.811  0.385  1.0
  Ti  Ti4  1  0.678  0.678  0.953  1.0
  Ti  Ti5  1  0.322  0.322  0.047  1.0
  Ti  Ti6  1  0.000  0.000  0.000  1.0
  Al  Al7  1  0.158  0.158  0.277  1.0
  Al  Al8  1  0.842  0.842  0.723  1.0
  O  O9  1  0.774  0.774  0.603  1.0
  O  O10  1  0.226  0.226  0.397  1.0
  O  O11  1  0.393  0.393  0.695  1.0
  O  O12  1  0.607  0.607  0.305  1.0
  O  O13  1  0.800  0.800  0.907  1.0
  O  O14  1  0.200  0.200  0.093  1.0
  O  O15  1  0.574  0.574  0.992  1.0
  O  O16  1  0.992  0.992  0.213  1.0
  O  O17  1  0.008  0.008  0.787  1.0
  O  O18  1  0.813  0.813  0.186  1.0
  O  O19  1  0.187  0.187  0.814  1.0
  O  O20  1  0.382  0.382  0.394  1.0
  O  O21  1  0.618  0.618  0.606  1.0
  O  O22  1  0.000  0.000  0.500  1.0
  O  O23  1  0.426  0.426  0.008  1.0
[/CIF]
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The compound described by Ti7Al2O15 crystallizes in the monoclinic C2/m space group. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(7), two equivalent O(5), and two equivalent O(8) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Al(1)O4 tetrahedra, and edges with three equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. In the second Ti site, Ti(2) is bonded to one O(6), two equivalent O(7), and three equivalent O(1) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with three equivalent Al(1)O4 tetrahedra, and edges with four equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. In the third Ti site, Ti(3) is bonded to one O(4), two equivalent O(6), and three equivalent O(3) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with three equivalent Al(1)O4 tetrahedra, and edges with four equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the fourth Ti site, Ti(4) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 49°. Al(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra, and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Ti(2) and one Al(1) atom to form a mixture of distorted corner and edge-sharing OTi3Al tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ti(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded to three equivalent Ti(3) and one Al(1) atom to form a mixture of distorted corner and edge-sharing OTi3Al tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(4) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(4) and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ti(2) and two equivalent Ti(3) atoms. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Ti(1) and two equivalent Ti(2) atoms. In the eighth O site, O(8) is bonded in a square co-planar geometry to four equivalent Ti(1) atoms. is represented by the CIF card [CIF]
data_Ti7Al2O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.157
_cell_length_b   9.157
_cell_length_c   9.454
_cell_angle_alpha   81.567
_cell_angle_beta   81.567
_cell_angle_gamma   18.678
_symmetry_Int_Tables_number   1
_cell_volume   251.019
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ti  Ti0  1  0.509  0.509  0.649  1.0
  Ti  Ti1  1  0.491  0.491  0.351  1.0
  Ti  Ti2  1  0.189  0.189  0.615  1.0
  Ti  Ti3  1  0.811  0.811  0.385  1.0
  Ti  Ti4  1  0.678  0.678  0.953  1.0
  Ti  Ti5  1  0.322  0.322  0.047  1.0
  Ti  Ti6  1  0.000  0.000  0.000  1.0
  Al  Al7  1  0.158  0.158  0.277  1.0
  Al  Al8  1  0.842  0.842  0.723  1.0
  O  O9  1  0.774  0.774  0.603  1.0
  O  O10  1  0.226  0.226  0.397  1.0
  O  O11  1  0.393  0.393  0.695  1.0
  O  O12  1  0.607  0.607  0.305  1.0
  O  O13  1  0.800  0.800  0.907  1.0
  O  O14  1  0.200  0.200  0.093  1.0
  O  O15  1  0.574  0.574  0.992  1.0
  O  O16  1  0.992  0.992  0.213  1.0
  O  O17  1  0.008  0.008  0.787  1.0
  O  O18  1  0.813  0.813  0.186  1.0
  O  O19  1  0.187  0.187  0.814  1.0
  O  O20  1  0.382  0.382  0.394  1.0
  O  O21  1  0.618  0.618  0.606  1.0
  O  O22  1  0.000  0.000  0.500  1.0
  O  O23  1  0.426  0.426  0.008  1.0
[/CIF]
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