data_[Mg4Cu4Se2]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pmmn]
_cell_length_a [3.6468]
_cell_length_b [4.0920]
_cell_length_c [12.2311]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [59]
_chemical_formula_structural [Mg2Cu2Se]
_chemical_formula_sum '[Mg4 Cu4 Se2]'
_cell_volume [182.5235]
_cell_formula_units_Z [2]
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  2  0.0000  0.5000  0.1640  1
  Mg  Mg1  2  0.0000  0.5000  0.5242  1
  Cu  Cu2  2  0.0000  0.0000  0.0054  1
  Cu  Cu3  2  0.0000  0.0000  0.6478  1
  Se  Se4  2  0.0000  0.5000  0.7619  1
]