data_Na4HfNb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.86
_cell_length_b   5.86
_cell_length_c   5.86
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na4HfNb
_chemical_formula_sum   'Na4 Hf1 Nb1'
_cell_volume   142.44
_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  0.1  0.1  0.19  1.0
  Na  Na2  1  0.1  0.19  0.1  1.0
  Na  Na3  1  0.19  0.1  0.1  1.0
  Na  Na4  1  0.19  0.19  0.19  1.0
  Hf  Hf0  1  0.07  0.07  0.07  1.0
  Nb  Nb5  1  0.0  0.0  0.0  1.0

data_Na4HfNb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.86
_cell_length_b   5.86
_cell_length_c   14.36
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na4HfNb
_chemical_formula_sum   'Na12 Hf3 Nb3'
_cell_volume   427.33
_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  9  0.03  0.05  0.87  1.0
  Na  Na1  3  0.0  0.0  0.81  1.0
  Hf  Hf2  3  0.0  0.0  0.93  1.0
  Nb  Nb3  3  0.0  0.0  0.0  1.0

Na Na Na Na Hf Nb
Na Na Na Na Hf Nb 0 2 o o o 0 1 o o o 0 3 o o o 0 4 o o o 1 2 o o o 1 3 o o o 1 4 o o o 2 3 o o o 2 4 o o o 4 5 o o o 
Na4HfNb crystallizes in the trigonal R3m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one Hf(1) atom. The Na(1)-Na(2) bond length is 0.83 Å. Both Na(1)-Na(1) bond lengths are 0.48 Å. The Na(1)-Hf(1) bond length is 0.89 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to three equivalent Na(1) and three equivalent Nb(1) atoms. All Na(2)-Nb(1) bond lengths are 3.99 Å. Hf(1) is bonded in a 4-coordinate geometry to three equivalent Na(1) and one Nb(1) atom. The Hf(1)-Nb(1) bond length is 1.04 Å. Nb(1) is bonded in a single-bond geometry to three equivalent Na(2) and one Hf(1) atom.