data_Na4Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.27
_cell_length_b   9.27
_cell_length_c   9.27
_cell_angle_alpha   109.47
_cell_angle_beta   109.47
_cell_angle_gamma   109.47
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na4Nb
_chemical_formula_sum   'Na16 Nb4'
_cell_volume   613.03
_cell_formula_units_Z   4
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  0.09  0.09  0.09  1.0
  Na  Na1  1  0.73  0.27  0.27  1.0
  Na  Na2  1  0.27  0.73  0.27  1.0
  Na  Na3  1  0.27  0.27  0.73  1.0
  Na  Na4  1  0.0  0.0  0.12  1.0
  Na  Na5  1  0.0  0.0  0.58  1.0
  Na  Na6  1  0.0  0.12  0.0  1.0
  Na  Na7  1  0.0  0.58  0.0  1.0
  Na  Na8  1  0.12  0.0  0.0  1.0
  Na  Na9  1  0.58  0.0  0.0  1.0
  Na  Na10  1  0.35  0.0  0.68  1.0
  Na  Na11  1  0.0  0.35  0.68  1.0
  Na  Na12  1  0.0  0.68  0.35  1.0
  Na  Na13  1  0.35  0.68  0.0  1.0
  Na  Na14  1  0.68  0.35  0.0  1.0
  Na  Na15  1  0.68  0.0  0.35  1.0
  Nb  Nb16  1  0.19  0.19  0.19  1.0
  Nb  Nb17  1  0.84  0.16  0.16  1.0
  Nb  Nb18  1  0.16  0.84  0.16  1.0
  Nb  Nb19  1  0.16  0.16  0.84  1.0

data_Na4Nb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   15.14
_cell_length_b   15.14
_cell_length_c   9.27
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na4Nb
_chemical_formula_sum   'Na48 Nb12'
_cell_volume   1839.09
_cell_formula_units_Z   12
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+2/3, y+1/3, z+1/3'
  8  '-y+2/3, x-y+1/3, z+1/3'
  9  '-x+y+2/3, -x+1/3, z+1/3'
  10  '-y+2/3, -x+1/3, z+1/3'
  11  '-x+y+2/3, y+1/3, z+1/3'
  12  'x+2/3, x-y+1/3, z+1/3'
  13  'x+1/3, y+2/3, z+2/3'
  14  '-y+1/3, x-y+2/3, z+2/3'
  15  '-x+y+1/3, -x+2/3, z+2/3'
  16  '-y+1/3, -x+2/3, z+2/3'
  17  '-x+y+1/3, y+2/3, z+2/3'
  18  'x+1/3, x-y+2/3, z+2/3'
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  18  0.0  0.32  0.68  1.0
  Na  Na1  9  0.06  0.53  0.53  1.0
  Na  Na2  9  0.08  0.04  0.04  1.0
  Na  Na3  9  0.18  0.35  0.09  1.0
  Na  Na4  3  0.0  0.0  0.09  1.0
  Nb  Nb5  9  0.11  0.22  0.05  1.0
  Nb  Nb6  3  0.0  0.0  0.19  1.0

Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Nb Nb Nb Nb