data_MgNb2Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.45
_cell_length_b   5.45
_cell_length_c   5.45
_cell_angle_alpha   148.07
_cell_angle_beta   126.39
_cell_angle_gamma   63.77
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNb2Cu
_chemical_formula_sum   'Mg1 Nb2 Cu1'
_cell_volume   68.33
_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  Mg1  1  0.0  0.0  0.73  1.0
  Nb  Nb2  1  0.5  0.0  0.09  1.0
  Nb  Nb3  1  0.0  0.0  0.46  1.0
  Cu  Cu0  1  0.5  0.0  0.61  1.0

data_MgNb2Cu
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.0
_cell_length_b   4.92
_cell_length_c   5.45
_cell_angle_alpha   116.8
_cell_angle_beta   105.97
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNb2Cu
_chemical_formula_sum   'Mg1 Nb2 Cu1'
_cell_volume   68.33
_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  0.27  0.27  0.27  1.0
  Nb  Nb1  1  0.41  0.91  0.41  1.0
  Nb  Nb2  1  0.54  0.54  0.54  1.0
  Cu  Cu3  1  0.89  0.39  0.89  1.0

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