The crystal structure described by Rb2NaAl6F21 crystallizes in the monoclinic C2 space group. Rb(1) is bonded in a 12-coordinate geometry to one F(11), one F(2), one F(3), one F(5), one F(7), one F(8), two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms. Na(1) is bonded to two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms to form NaF6 octahedra that share corners with two equivalent Al(1)F6 octahedra, corners with two equivalent Al(2)F6 octahedra, and corners with two equivalent Al(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one F(11), one F(3), one F(4), one F(6), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-63°. In the second Al site, Al(2) is bonded to one F(10), one F(2), one F(4), one F(5), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-56°. In the third Al site, Al(3) is bonded to one F(1), one F(11), one F(2), one F(3), one F(5), and one F(9) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra,  a cornercorner with one Al(3)F6 octahedra, corners with two equivalent Al(1)F6 octahedra, and corners with two equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 14-60°. There are eleven inequivalent F sites. In the first F site, F(1) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(3) atom. In the second F site, F(2) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the third F site, F(3) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom. In the fourth F site, F(4) is bonded in a linear geometry to one Al(1) and one Al(2) atom. In the fifth F site, F(5) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the sixth F site, F(6) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(1) atom. In the seventh F site, F(7) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the eighth F site, F(8) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the ninth F site, F(9) is bonded in a linear geometry to two equivalent Al(3) atoms. In the tenth F site, F(10) is bonded in a 3-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(2) atom. In the eleventh F site, F(11) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom. is represented by the CIF file [CIF]
data_Rb2NaAl6F21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.076
_cell_length_b   7.076
_cell_length_c   10.354
_cell_angle_alpha   70.064
_cell_angle_beta   70.064
_cell_angle_gamma   60.060
_symmetry_Int_Tables_number   1
_cell_volume   412.893
_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
  Rb  Rb0  1  0.134  0.137  0.594  1.0
  Rb  Rb1  1  0.863  0.866  0.406  1.0
  Na  Na2  1  0.514  0.486  0.500  1.0
  Al  Al3  1  0.457  0.915  0.192  1.0
  Al  Al4  1  0.085  0.543  0.808  1.0
  Al  Al5  1  0.959  0.416  0.190  1.0
  Al  Al6  1  0.461  0.412  0.191  1.0
  Al  Al7  1  0.588  0.539  0.809  1.0
  Al  Al8  1  0.584  0.041  0.810  1.0
  F  F9  1  0.680  0.567  0.625  1.0
  F  F10  1  0.433  0.320  0.375  1.0
  F  F11  1  0.166  0.490  0.204  1.0
  F  F12  1  0.510  0.834  0.796  1.0
  F  F13  1  0.870  0.456  0.829  1.0
  F  F14  1  0.513  0.957  0.001  1.0
  F  F15  1  0.756  0.343  0.169  1.0
  F  F16  1  0.137  0.595  0.622  1.0
  F  F17  1  0.876  0.832  0.812  1.0
  F  F18  1  0.750  0.709  0.186  1.0
  F  F19  1  0.657  0.244  0.831  1.0
  F  F20  1  0.493  0.507  0.000  1.0
  F  F21  1  0.879  0.350  0.374  1.0
  F  F22  1  0.302  0.626  0.795  1.0
  F  F23  1  0.405  0.863  0.378  1.0
  F  F24  1  0.291  0.250  0.814  1.0
  F  F25  1  0.544  0.130  0.171  1.0
  F  F26  1  0.374  0.698  0.205  1.0
  F  F27  1  0.168  0.124  0.188  1.0
  F  F28  1  0.043  0.487  0.999  1.0
  F  F29  1  0.650  0.121  0.626  1.0
[/CIF]
.
The crystal structure described by Rb2NaAl6F21 crystallizes in the monoclinic C2 space group. Rb(1) is bonded in a 12-coordinate geometry to one F(11), one F(2), one F(3), one F(5), one F(7), one F(8), two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms. Na(1) is bonded to two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms to form NaF6 octahedra that share corners with two equivalent Al(1)F6 octahedra, corners with two equivalent Al(2)F6 octahedra, and corners with two equivalent Al(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one F(11), one F(3), one F(4), one F(6), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-63°. In the second Al site, Al(2) is bonded to one F(10), one F(2), one F(4), one F(5), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-56°. In the third Al site, Al(3) is bonded to one F(1), one F(11), one F(2), one F(3), one F(5), and one F(9) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra,  a cornercorner with one Al(3)F6 octahedra, corners with two equivalent Al(1)F6 octahedra, and corners with two equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 14-60°. There are eleven inequivalent F sites. In the first F site, F(1) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(3) atom. In the second F site, F(2) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the third F site, F(3) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom. In the fourth F site, F(4) is bonded in a linear geometry to one Al(1) and one Al(2) atom. In the fifth F site, F(5) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the sixth F site, F(6) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(1) atom. In the seventh F site, F(7) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the eighth F site, F(8) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the ninth F site, F(9) is bonded in a linear geometry to two equivalent Al(3) atoms. In the tenth F site, F(10) is bonded in a 3-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(2) atom. In the eleventh F site, F(11) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom. is represented by the CIF file [CIF]
data_Rb2NaAl6F21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.076
_cell_length_b   7.076
_cell_length_c   10.354
_cell_angle_alpha   70.064
_cell_angle_beta   70.064
_cell_angle_gamma   60.060
_symmetry_Int_Tables_number   1
_cell_volume   412.893
_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
  Rb  Rb0  1  0.134  0.137  0.594  1.0
  Rb  Rb1  1  0.863  0.866  0.406  1.0
  Na  Na2  1  0.514  0.486  0.500  1.0
  Al  Al3  1  0.457  0.915  0.192  1.0
  Al  Al4  1  0.085  0.543  0.808  1.0
  Al  Al5  1  0.959  0.416  0.190  1.0
  Al  Al6  1  0.461  0.412  0.191  1.0
  Al  Al7  1  0.588  0.539  0.809  1.0
  Al  Al8  1  0.584  0.041  0.810  1.0
  F  F9  1  0.680  0.567  0.625  1.0
  F  F10  1  0.433  0.320  0.375  1.0
  F  F11  1  0.166  0.490  0.204  1.0
  F  F12  1  0.510  0.834  0.796  1.0
  F  F13  1  0.870  0.456  0.829  1.0
  F  F14  1  0.513  0.957  0.001  1.0
  F  F15  1  0.756  0.343  0.169  1.0
  F  F16  1  0.137  0.595  0.622  1.0
  F  F17  1  0.876  0.832  0.812  1.0
  F  F18  1  0.750  0.709  0.186  1.0
  F  F19  1  0.657  0.244  0.831  1.0
  F  F20  1  0.493  0.507  0.000  1.0
  F  F21  1  0.879  0.350  0.374  1.0
  F  F22  1  0.302  0.626  0.795  1.0
  F  F23  1  0.405  0.863  0.378  1.0
  F  F24  1  0.291  0.250  0.814  1.0
  F  F25  1  0.544  0.130  0.171  1.0
  F  F26  1  0.374  0.698  0.205  1.0
  F  F27  1  0.168  0.124  0.188  1.0
  F  F28  1  0.043  0.487  0.999  1.0
  F  F29  1  0.650  0.121  0.626  1.0
[/CIF]
.