The crystal structure described by Na17Al5O16 crystallizes in the monoclinic Cm space group. There are nine inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted see-saw-like geometry to one O(7), one O(8), and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(9) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(7), one O(8), and one O(9) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(9) atom. In the fifth Na site, Na(5) is bonded in a 3-coordinate geometry to one O(2), one O(3), one O(7), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(7), one O(8), and one O(9) atom. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(9) atom. In the eighth Na site, Na(8) is bonded in a 4-coordinate geometry to one O(7), one O(8), and two equivalent O(2) atoms. In the ninth Na site, Na(9) is bonded in a 4-coordinate geometry to one O(1), one O(6), and two equivalent O(4) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), one O(3), one O(7), and one O(8) atom to form corner-sharing AlO4 tetrahedra. In the second Al site, Al(2) is bonded to one O(3), one O(4), one O(5), and one O(9) atom to form corner-sharing AlO4 tetrahedra. In the third Al site, Al(3) is bonded to one O(1), one O(6), and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(9), two equivalent Na(4), two equivalent Na(7), and one Al(3) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(5), two equivalent Na(1), two equivalent Na(8), and one Al(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(5), one Na(6), one Al(1), and one Al(2) atom. In the fourth O site, O(4) is bonded to one Na(2), one Na(4), one Na(7), one Na(9), one Al(2), and one Al(3) atom to form distorted edge-sharing ONa4Al2 octahedra. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(6), one Na(7), and one Al(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(9), two equivalent Na(4), two equivalent Na(7), and one Al(3) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(5), one Na(6), one Na(8), and one Al(1) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(5), one Na(6), one Na(8), and one Al(1) atom. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(6), one Na(7), and one Al(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na17Al5O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   16.648
_cell_length_b   16.648
_cell_length_c   5.938
_cell_angle_alpha   84.946
_cell_angle_beta   84.946
_cell_angle_gamma   159.492
_symmetry_Int_Tables_number   1
_cell_volume   501.022
_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
  Na  Na0  1  0.329  0.788  0.052  1.0
  Na  Na1  1  0.087  0.910  0.193  1.0
  Na  Na2  1  0.788  0.329  0.052  1.0
  Na  Na3  1  0.396  0.672  0.054  1.0
  Na  Na4  1  0.507  0.415  0.612  1.0
  Na  Na5  1  0.910  0.087  0.193  1.0
  Na  Na6  1  0.826  0.179  0.465  1.0
  Na  Na7  1  0.323  0.598  0.586  1.0
  Na  Na8  1  0.598  0.323  0.586  1.0
  Na  Na9  1  0.580  0.488  0.077  1.0
  Na  Na10  1  0.179  0.826  0.465  1.0
  Na  Na11  1  0.671  0.222  0.626  1.0
  Na  Na12  1  0.672  0.396  0.054  1.0
  Na  Na13  1  0.488  0.580  0.077  1.0
  Na  Na14  1  0.415  0.507  0.612  1.0
  Na  Na15  1  0.222  0.671  0.626  1.0
  Na  Na16  1  0.998  0.998  0.489  1.0
  Al  Al17  1  0.817  0.178  0.992  1.0
  Al  Al18  1  0.178  0.817  0.992  1.0
  Al  Al19  1  0.906  0.087  0.674  1.0
  Al  Al20  1  0.087  0.906  0.674  1.0
  Al  Al21  1  0.997  0.997  0.005  1.0
  O  O22  1  0.283  0.283  0.020  1.0
  O  O23  1  0.788  0.221  0.769  1.0
  O  O24  1  0.127  0.868  0.876  1.0
  O  O25  1  0.953  0.040  0.826  1.0
  O  O26  1  0.375  0.189  0.375  1.0
  O  O27  1  0.040  0.953  0.826  1.0
  O  O28  1  0.711  0.711  0.304  1.0
  O  O29  1  0.895  0.524  0.291  1.0
  O  O30  1  0.095  0.466  0.015  1.0
  O  O31  1  0.524  0.895  0.291  1.0
  O  O32  1  0.189  0.375  0.375  1.0
  O  O33  1  0.618  0.805  0.658  1.0
  O  O34  1  0.221  0.788  0.769  1.0
  O  O35  1  0.805  0.618  0.658  1.0
  O  O36  1  0.868  0.127  0.876  1.0
  O  O37  1  0.466  0.095  0.015  1.0
[/CIF]
.
The crystal structure described by Na17Al5O16 crystallizes in the monoclinic Cm space group. There are nine inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted see-saw-like geometry to one O(7), one O(8), and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(9) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(7), one O(8), and one O(9) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(9) atom. In the fifth Na site, Na(5) is bonded in a 3-coordinate geometry to one O(2), one O(3), one O(7), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(7), one O(8), and one O(9) atom. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(9) atom. In the eighth Na site, Na(8) is bonded in a 4-coordinate geometry to one O(7), one O(8), and two equivalent O(2) atoms. In the ninth Na site, Na(9) is bonded in a 4-coordinate geometry to one O(1), one O(6), and two equivalent O(4) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), one O(3), one O(7), and one O(8) atom to form corner-sharing AlO4 tetrahedra. In the second Al site, Al(2) is bonded to one O(3), one O(4), one O(5), and one O(9) atom to form corner-sharing AlO4 tetrahedra. In the third Al site, Al(3) is bonded to one O(1), one O(6), and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(9), two equivalent Na(4), two equivalent Na(7), and one Al(3) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(5), two equivalent Na(1), two equivalent Na(8), and one Al(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(5), one Na(6), one Al(1), and one Al(2) atom. In the fourth O site, O(4) is bonded to one Na(2), one Na(4), one Na(7), one Na(9), one Al(2), and one Al(3) atom to form distorted edge-sharing ONa4Al2 octahedra. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(6), one Na(7), and one Al(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(9), two equivalent Na(4), two equivalent Na(7), and one Al(3) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(5), one Na(6), one Na(8), and one Al(1) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(5), one Na(6), one Na(8), and one Al(1) atom. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(6), one Na(7), and one Al(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na17Al5O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   16.648
_cell_length_b   16.648
_cell_length_c   5.938
_cell_angle_alpha   84.946
_cell_angle_beta   84.946
_cell_angle_gamma   159.492
_symmetry_Int_Tables_number   1
_cell_volume   501.022
_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
  Na  Na0  1  0.329  0.788  0.052  1.0
  Na  Na1  1  0.087  0.910  0.193  1.0
  Na  Na2  1  0.788  0.329  0.052  1.0
  Na  Na3  1  0.396  0.672  0.054  1.0
  Na  Na4  1  0.507  0.415  0.612  1.0
  Na  Na5  1  0.910  0.087  0.193  1.0
  Na  Na6  1  0.826  0.179  0.465  1.0
  Na  Na7  1  0.323  0.598  0.586  1.0
  Na  Na8  1  0.598  0.323  0.586  1.0
  Na  Na9  1  0.580  0.488  0.077  1.0
  Na  Na10  1  0.179  0.826  0.465  1.0
  Na  Na11  1  0.671  0.222  0.626  1.0
  Na  Na12  1  0.672  0.396  0.054  1.0
  Na  Na13  1  0.488  0.580  0.077  1.0
  Na  Na14  1  0.415  0.507  0.612  1.0
  Na  Na15  1  0.222  0.671  0.626  1.0
  Na  Na16  1  0.998  0.998  0.489  1.0
  Al  Al17  1  0.817  0.178  0.992  1.0
  Al  Al18  1  0.178  0.817  0.992  1.0
  Al  Al19  1  0.906  0.087  0.674  1.0
  Al  Al20  1  0.087  0.906  0.674  1.0
  Al  Al21  1  0.997  0.997  0.005  1.0
  O  O22  1  0.283  0.283  0.020  1.0
  O  O23  1  0.788  0.221  0.769  1.0
  O  O24  1  0.127  0.868  0.876  1.0
  O  O25  1  0.953  0.040  0.826  1.0
  O  O26  1  0.375  0.189  0.375  1.0
  O  O27  1  0.040  0.953  0.826  1.0
  O  O28  1  0.711  0.711  0.304  1.0
  O  O29  1  0.895  0.524  0.291  1.0
  O  O30  1  0.095  0.466  0.015  1.0
  O  O31  1  0.524  0.895  0.291  1.0
  O  O32  1  0.189  0.375  0.375  1.0
  O  O33  1  0.618  0.805  0.658  1.0
  O  O34  1  0.221  0.788  0.769  1.0
  O  O35  1  0.805  0.618  0.658  1.0
  O  O36  1  0.868  0.127  0.876  1.0
  O  O37  1  0.466  0.095  0.015  1.0
[/CIF]
.