data_Mg(ZnSe)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.32
_cell_length_b   7.32
_cell_length_c   7.32
_cell_angle_alpha   146.45
_cell_angle_beta   146.45
_cell_angle_gamma   48.18
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg(ZnSe)2
_chemical_formula_sum   'Mg1 Zn2 Se2'
_cell_volume   119.2
_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
  Zn  Zn3  1  0.0  0.11  0.34  1.0
  Zn  Zn4  1  0.11  0.0  0.34  1.0
  Se  Se1  1  0.0  0.0  0.55  1.0
  Se  Se2  1  0.0  0.0  0.81  1.0

data_Mg(ZnSe)2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.97
_cell_length_b   5.97
_cell_length_c   7.32
_cell_angle_alpha   90.0
_cell_angle_beta   114.09
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg(ZnSe)2
_chemical_formula_sum   'Mg2 Zn4 Se4'
_cell_volume   238.41
_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
  Zn  Zn1  4  0.28  0.06  0.23  1.0
  Se  Se2  2  0.05  0.5  0.55  1.0
  Se  Se3  2  0.31  0.5  0.81  1.0

Mg Zn Zn Se Se