data_Ca2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.51
_cell_length_b   7.51
_cell_length_c   7.14
_cell_angle_alpha   110.12
_cell_angle_beta   110.12
_cell_angle_gamma   29.78
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2Se
_chemical_formula_sum   'Ca4 Se2'
_cell_volume   187.11
_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
  Ca  Ca0  1  0.35  0.0  0.83  1.0
  Ca  Ca1  1  0.87  0.0  0.69  1.0
  Ca  Ca2  1  0.12  0.0  0.98  1.0
  Ca  Ca3  1  0.64  0.0  0.84  1.0
  Se  Se4  1  0.23  0.0  0.42  1.0
  Se  Se5  1  0.75  0.0  0.25  1.0

data_Ca2Se
_symmetry_space_group_name_H-M   P-1
_cell_length_a   3.86
_cell_length_b   7.14
_cell_length_c   7.51
_cell_angle_alpha   110.12
_cell_angle_beta   104.89
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Ca2Se
_chemical_formula_sum   'Ca4 Se2'
_cell_volume   187.11
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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
  Ca  Ca0  2  0.0  0.35  0.37  1.0
  Ca  Ca1  2  0.0  0.5  0.85  1.0
  Se  Se2  2  0.0  0.08  0.74  1.0

Ca Ca Ca Ca Se Se