data_ZnNiSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.05
_cell_length_b   5.05
_cell_length_c   5.05
_cell_angle_alpha   139.3
_cell_angle_beta   112.23
_cell_angle_gamma   82.16
_symmetry_Int_Tables_number   1
_chemical_formula_structural   ZnNiSe2
_chemical_formula_sum   'Zn1 Ni1 Se2'
_cell_volume   75.19
_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
  Zn  Zn3  1  0.0  0.0  0.81  1.0
  Ni  Ni0  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.0  0.81  0.28  1.0
  Se  Se2  1  0.76  0.0  0.53  1.0

data_ZnNiSe2
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.51
_cell_length_b   5.05
_cell_length_c   5.05
_cell_angle_alpha   67.77
_cell_angle_beta   69.65
_cell_angle_gamma   69.65
_symmetry_Int_Tables_number   1
_chemical_formula_structural   ZnNiSe2
_chemical_formula_sum   'Zn1 Ni1 Se2'
_cell_volume   75.19
_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
  Zn  Zn0  1  0.0  0.0  0.81  1.0
  Ni  Ni1  1  0.0  0.0  0.0  1.0
  Se  Se2  1  0.0  0.24  0.53  1.0
  Se  Se3  1  0.81  -0.0  0.47  1.0

Zn Ni Se Se
Zn Ni Se Se 0 1 o o + 0 2 o - o 0 3 - o o 2 3 - + o 