The compound described by Na2SiF6 crystallizes in the trigonal P321 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms to form distorted NaF6 octahedra that share corners with two equivalent Si(2)F6 octahedra, corners with six equivalent Na(2)F6 octahedra, and edges with two equivalent Si(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 47-64°. In the second Na site, Na(2) is bonded to two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms to form NaF6 octahedra that share corners with four equivalent Si(1)F6 octahedra, corners with six equivalent Na(1)F6 octahedra, and  an edgeedge with one Si(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 43-64°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent F(1) and three equivalent F(2) atoms to form SiF6 octahedra that share corners with six equivalent Na(2)F6 octahedra and edges with three equivalent Na(1)F6 octahedra. The corner-sharing octahedral tilt angles are 43°. In the second Si site, Si(2) is bonded to six equivalent F(3) atoms to form SiF6 octahedra that share corners with six equivalent Na(1)F6 octahedra and edges with three equivalent Na(2)F6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one Si(1) atom. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one Si(1) atom. In the third F site, F(3) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one Si(2) atom. is represented by the CIF card [CIF]
data_Na2SiF6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.803
_cell_length_b   8.803
_cell_length_c   4.968
_cell_angle_alpha   89.999
_cell_angle_beta   90.000
_cell_angle_gamma   120.004
_symmetry_Int_Tables_number   1
_cell_volume   333.340
_cell_formula_units_Z   3
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  1.000  0.290  0.500  1.0
  Na  Na1  1  0.290  0.000  0.500  1.0
  Na  Na2  1  0.710  0.710  0.500  1.0
  Na  Na3  1  1.000  0.625  1.000  1.0
  Na  Na4  1  0.625  0.000  1.000  1.0
  Na  Na5  1  0.375  0.375  1.000  1.0
  Si  Si6  1  0.667  0.333  0.494  1.0
  Si  Si7  1  0.333  0.667  0.506  1.0
  Si  Si8  1  1.000  1.000  0.000  1.0
  F  F9  1  0.741  0.226  0.691  1.0
  F  F10  1  0.774  0.515  0.691  1.0
  F  F11  1  0.485  0.259  0.691  1.0
  F  F12  1  0.515  0.774  0.309  1.0
  F  F13  1  0.259  0.485  0.309  1.0
  F  F14  1  0.226  0.741  0.309  1.0
  F  F15  1  0.595  0.443  0.297  1.0
  F  F16  1  0.557  0.152  0.297  1.0
  F  F17  1  0.848  0.405  0.297  1.0
  F  F18  1  0.085  0.903  0.805  1.0
  F  F19  1  0.097  0.182  0.805  1.0
  F  F20  1  0.818  0.915  0.805  1.0
  F  F21  1  0.182  0.098  0.195  1.0
  F  F22  1  0.915  0.818  0.195  1.0
  F  F23  1  0.902  0.085  0.195  1.0
  F  F24  1  0.443  0.596  0.703  1.0
  F  F25  1  0.404  0.848  0.703  1.0
  F  F26  1  0.152  0.557  0.703  1.0
[/CIF]
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The compound described by Na2SiF6 crystallizes in the trigonal P321 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms to form distorted NaF6 octahedra that share corners with two equivalent Si(2)F6 octahedra, corners with six equivalent Na(2)F6 octahedra, and edges with two equivalent Si(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 47-64°. In the second Na site, Na(2) is bonded to two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms to form NaF6 octahedra that share corners with four equivalent Si(1)F6 octahedra, corners with six equivalent Na(1)F6 octahedra, and  an edgeedge with one Si(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 43-64°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent F(1) and three equivalent F(2) atoms to form SiF6 octahedra that share corners with six equivalent Na(2)F6 octahedra and edges with three equivalent Na(1)F6 octahedra. The corner-sharing octahedral tilt angles are 43°. In the second Si site, Si(2) is bonded to six equivalent F(3) atoms to form SiF6 octahedra that share corners with six equivalent Na(1)F6 octahedra and edges with three equivalent Na(2)F6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one Si(1) atom. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one Si(1) atom. In the third F site, F(3) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one Si(2) atom. is represented by the CIF card [CIF]
data_Na2SiF6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.803
_cell_length_b   8.803
_cell_length_c   4.968
_cell_angle_alpha   89.999
_cell_angle_beta   90.000
_cell_angle_gamma   120.004
_symmetry_Int_Tables_number   1
_cell_volume   333.340
_cell_formula_units_Z   3
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  1.000  0.290  0.500  1.0
  Na  Na1  1  0.290  0.000  0.500  1.0
  Na  Na2  1  0.710  0.710  0.500  1.0
  Na  Na3  1  1.000  0.625  1.000  1.0
  Na  Na4  1  0.625  0.000  1.000  1.0
  Na  Na5  1  0.375  0.375  1.000  1.0
  Si  Si6  1  0.667  0.333  0.494  1.0
  Si  Si7  1  0.333  0.667  0.506  1.0
  Si  Si8  1  1.000  1.000  0.000  1.0
  F  F9  1  0.741  0.226  0.691  1.0
  F  F10  1  0.774  0.515  0.691  1.0
  F  F11  1  0.485  0.259  0.691  1.0
  F  F12  1  0.515  0.774  0.309  1.0
  F  F13  1  0.259  0.485  0.309  1.0
  F  F14  1  0.226  0.741  0.309  1.0
  F  F15  1  0.595  0.443  0.297  1.0
  F  F16  1  0.557  0.152  0.297  1.0
  F  F17  1  0.848  0.405  0.297  1.0
  F  F18  1  0.085  0.903  0.805  1.0
  F  F19  1  0.097  0.182  0.805  1.0
  F  F20  1  0.818  0.915  0.805  1.0
  F  F21  1  0.182  0.098  0.195  1.0
  F  F22  1  0.915  0.818  0.195  1.0
  F  F23  1  0.902  0.085  0.195  1.0
  F  F24  1  0.443  0.596  0.703  1.0
  F  F25  1  0.404  0.848  0.703  1.0
  F  F26  1  0.152  0.557  0.703  1.0
[/CIF]
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