data_Na2NbBi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   5.2
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2NbBi
_chemical_formula_sum   'Na2 Nb1 Bi1'
_cell_volume   99.19
_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  Na1  1  0.0  0.0  0.0  1.0
  Na  Na2  1  0.84  0.84  0.84  1.0
  Nb  Nb3  1  0.67  0.67  0.67  1.0
  Bi  Bi0  1  0.51  0.51  0.51  1.0

data_Na2NbBi
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   12.73
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na2NbBi
_chemical_formula_sum   'Na6 Nb3 Bi3'
_cell_volume   297.58
_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
  Na  Na1  3  0.0  0.0  0.16  1.0
  Nb  Nb2  3  0.0  0.0  0.33  1.0
  Bi  Bi3  3  0.0  0.0  0.49  1.0

Na Na Nb Bi
Na2NbBi crystallizes in the trigonal R3m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one Na(2) and three equivalent Nb(1) atoms to form distorted NaNaNb3 trigonal pyramids that share  a cornercorner with one Nb(1)Na4Bi trigonal bipyramid, corners with six equivalent Na(1)NaNb3 trigonal pyramids, and edges with three equivalent Bi(1)Na3Nb trigonal pyramids. The Na(1)-Na(2) bond length is 2.07 Å. All Na(1)-Nb(1) bond lengths are 3.00 Å. In the second Na site, Na(2) is bonded in a distorted single-bond geometry to one Na(1), one Nb(1), and three equivalent Bi(1) atoms. The Na(2)-Nb(1) bond length is 2.07 Å. All Na(2)-Bi(1) bond lengths are 3.00 Å. Nb(1) is bonded to one Na(2), three equivalent Na(1), and one Bi(1) atom to form distorted NbNa4Bi trigonal bipyramids that share corners with six equivalent Nb(1)Na4Bi trigonal bipyramids,  a cornercorner with one Na(1)NaNb3 trigonal pyramid, and corners with three equivalent Bi(1)Na3Nb trigonal pyramids. The Nb(1)-Bi(1) bond length is 2.07 Å. Bi(1) is bonded to three equivalent Na(2) and one Nb(1) atom to form distorted BiNa3Nb trigonal pyramids that share corners with three equivalent Nb(1)Na4Bi trigonal bipyramids, corners with six equivalent Bi(1)Na3Nb trigonal pyramids, and edges with three equivalent Na(1)NaNb3 trigonal pyramids.