data_Mg2CuSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.39
_cell_length_b   5.39
_cell_length_c   5.39
_cell_angle_alpha   139.77
_cell_angle_beta   97.48
_cell_angle_gamma   96.1
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2CuSe2
_chemical_formula_sum   'Mg2 Cu1 Se2'
_cell_volume   95.21
_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  0.86  0.0  0.11  1.0
  Mg  Mg2  1  0.0  0.56  0.5  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.0  0.72  0.61  1.0
  Se  Se4  1  0.86  0.84  0.0  1.0

data_Mg2CuSe2
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.71
_cell_length_b   5.39
_cell_length_c   5.39
_cell_angle_alpha   82.52
_cell_angle_beta   69.88
_cell_angle_gamma   69.88
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2CuSe2
_chemical_formula_sum   'Mg2 Cu1 Se2'
_cell_volume   95.21
_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  0.14  0.11  1.0
  Mg  Mg1  1  0.56  0.0  0.94  1.0
  Cu  Cu2  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.72  0.0  0.89  1.0
  Se  Se4  1  0.84  0.14  0.16  1.0

Mg Mg Cu Se Se