data_NaNbSi4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.02
_cell_length_b   5.02
_cell_length_c   5.02
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaNbSi4
_chemical_formula_sum   'Na1 Nb1 Si4'
_cell_volume   89.72
_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  0.0  0.0  0.0  1.0
  Nb  Nb1  1  0.78  0.78  0.78  1.0
  Si  Si2  1  0.67  0.67  0.43  1.0
  Si  Si3  1  0.67  0.43  0.67  1.0
  Si  Si4  1  0.43  0.67  0.67  1.0
  Si  Si5  1  0.43  0.43  0.43  1.0

data_NaNbSi4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.02
_cell_length_b   5.02
_cell_length_c   12.31
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaNbSi4
_chemical_formula_sum   'Na3 Nb3 Si12'
_cell_volume   269.15
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.0  1.0
  Nb  Nb1  3  0.0  0.0  0.22  1.0
  Si  Si2  9  0.16  0.08  0.41  1.0
  Si  Si3  3  0.0  0.0  0.57  1.0

Na Nb Si Si Si Si
NaNbSi4 crystallizes in the trigonal R3m space group. Na(1) is bonded in a 3-coordinate geometry to four equivalent Nb(1), three equivalent Si(1), and three equivalent Si(2) atoms. There is one shorter (2.75 Å) and three longer (3.20 Å) Na(1)-Nb(1) bond lengths. All Na(1)-Si(1) bond lengths are 2.38 Å. All Na(1)-Si(2) bond lengths are 3.15 Å. Nb(1) is bonded in a 13-coordinate geometry to four equivalent Na(1), three equivalent Si(2), and six equivalent Si(1) atoms. All Nb(1)-Si(2) bond lengths are 2.90 Å. There are three shorter (2.36 Å) and three longer (2.87 Å) Nb(1)-Si(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a 9-coordinate geometry to three equivalent Na(1), three equivalent Nb(1), and three equivalent Si(1) atoms. All Si(2)-Si(1) bond lengths are 2.10 Å. In the second Si site, Si(1) is bonded in a 3-coordinate geometry to one Na(1), two equivalent Nb(1), one Si(2), and two equivalent Si(1) atoms. Both Si(1)-Si(1) bond lengths are 1.21 Å.