data_MgCu2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.19
_cell_length_b   8.19
_cell_length_c   8.19
_cell_angle_alpha   22.0
_cell_angle_beta   22.0
_cell_angle_gamma   22.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgCu2Se
_chemical_formula_sum   'Mg1 Cu2 Se1'
_cell_volume   67.48
_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  Mg2  1  0.0  0.0  0.0  1.0
  Cu  Cu0  1  0.0  0.0  0.83  1.0
  Cu  Cu1  1  0.0  0.0  0.12  1.0
  Se  Se3  1  0.0  0.0  0.98  1.0

data_MgCu2Se
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.41
_cell_length_b   3.12
_cell_length_c   8.19
_cell_angle_alpha   90.0
_cell_angle_beta   102.73
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MgCu2Se
_chemical_formula_sum   'Mg2 Cu4 Se2'
_cell_volume   134.95
_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
  Mg  Mg0  2  0.0  0.0  0.0  1.0
  Cu  Cu1  2  0.0  0.0  0.17  1.0
  Cu  Cu2  2  0.0  0.0  0.88  1.0
  Se  Se3  2  0.0  0.0  0.02  1.0

Mg Cu Cu Se
Mg Cu Cu Se 0 3 o o - 0 1 o o - 0 2 o o o 1 3 o o o 2 3 o o - 