data_MgNb3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.69
_cell_length_b   5.69
_cell_length_c   5.69
_cell_angle_alpha   117.6
_cell_angle_beta   117.6
_cell_angle_gamma   117.6
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNb3
_chemical_formula_sum   'Mg1 Nb3'
_cell_volume   73.28
_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
  Mg  Mg0  1  0.0  0.0  0.0  1.0
  Nb  Nb1  1  0.44  0.59  0.89  1.0
  Nb  Nb2  1  0.0  0.81  0.89  1.0
  Nb  Nb3  1  0.56  0.59  0.89  1.0

data_MgNb3
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.68
_cell_length_b   5.69
_cell_length_c   5.69
_cell_angle_alpha   117.6
_cell_angle_beta   99.01
_cell_angle_gamma   99.01
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNb3
_chemical_formula_sum   'Mg1 Nb3'
_cell_volume   73.28
_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
  Mg  Mg0  1  0.0  0.0  0.0  1.0
  Nb  Nb1  1  0.89  0.33  0.3  1.0
  Nb  Nb2  1  0.89  0.46  0.3  1.0
  Nb  Nb3  1  0.89  0.89  0.08  1.0

Mg Nb Nb Nb
Mg Nb Nb Nb 0 2 o - - 1 3 o o o 