data_NaCa2Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.02
_cell_length_b   12.02
_cell_length_c   12.02
_cell_angle_alpha   16.24
_cell_angle_beta   16.24
_cell_angle_gamma   16.24
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaCa2Nb
_chemical_formula_sum   'Na1 Ca2 Nb1'
_cell_volume   118.4
_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  Na2  1  0.0  0.0  0.0  1.0
  Ca  Ca0  1  0.0  0.0  0.5  1.0
  Ca  Ca1  1  0.0  0.0  0.08  1.0
  Nb  Nb3  1  0.0  0.0  0.79  1.0

data_NaCa2Nb
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.88
_cell_length_b   3.4
_cell_length_c   12.02
_cell_angle_alpha   90.0
_cell_angle_beta   99.38
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   NaCa2Nb
_chemical_formula_sum   'Na2 Ca4 Nb2'
_cell_volume   236.8
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.0  1.0
  Ca  Ca1  2  -0.0  0.0  0.5  1.0
  Ca  Ca2  2  0.0  0.0  0.92  1.0
  Nb  Nb3  2  -0.0  0.0  0.21  1.0

Na Ca Ca Nb
Na Ca Ca Nb 0 2 o o o 0 3 o o - 1 1 o + - 1 1 + - o 1 1 + o - 1 3 o o o 2 3 o o - 3 3 o + - 3 3 + - o 3 3 + o - 