data_Mg2CuSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.42
_cell_length_b   7.42
_cell_length_c   4.34
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   127.28
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2CuSe
_chemical_formula_sum   'Mg4 Cu2 Se2'
_cell_volume   189.84
_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  Mg2  1  0.98  0.77  0.08  1.0
  Mg  Mg3  1  0.61  0.23  0.25  1.0
  Mg  Mg4  1  0.61  0.77  0.08  1.0
  Mg  Mg5  1  0.98  0.23  0.25  1.0
  Cu  Cu0  1  0.0  0.0  0.17  1.0
  Cu  Cu1  1  0.0  0.0  0.0  1.0
  Se  Se6  1  0.29  0.41  0.08  1.0
  Se  Se7  1  0.29  0.59  0.25  1.0

data_Mg2CuSe
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.34
_cell_length_b   6.59
_cell_length_c   7.42
_cell_angle_alpha   116.36
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2CuSe
_chemical_formula_sum   'Mg4 Cu2 Se2'
_cell_volume   189.84
_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  1  0.08  0.23  0.21  1.0
  Mg  Mg1  1  0.08  0.23  0.84  1.0
  Mg  Mg2  1  0.25  0.77  0.38  1.0
  Mg  Mg3  1  0.25  0.77  0.74  1.0
  Cu  Cu4  1  0.0  0.0  0.0  1.0
  Cu  Cu5  1  0.17  0.0  0.0  1.0
  Se  Se6  1  0.08  0.59  0.88  1.0
  Se  Se7  1  0.25  0.41  0.7  1.0

Mg Mg Mg Mg Cu Cu Se Se
Mg Mg Mg Mg Cu Cu Se Se 0 5 + + o 0 4 + + o 0 1 o o o 1 6 o o o 1 2 o - o 1 3 o o o 2 7 o o o 2 6 o o o 2 5 + + o 2 4 + + o 3 5 + o o 3 4 + o o 3 6 + o o 3 7 + o o 4 5 o o o 6 7 o o o 