data_NaNi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.69
_cell_length_b   3.57
_cell_length_c   8.12
_cell_angle_alpha   90.0
_cell_angle_beta   90.68
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaNi
_chemical_formula_sum   'Na2 Ni2'
_cell_volume   77.97
_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
  Na  Na0  1  0.52  0.89  0.61  1.0
  Na  Na1  1  0.08  0.67  0.51  1.0
  Ni  Ni2  1  0.63  0.89  0.41  1.0
  Ni  Ni3  1  0.97  0.67  0.7  1.0

data_NaNi
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.69
_cell_length_b   3.57
_cell_length_c   8.12
_cell_angle_alpha   90.0
_cell_angle_beta   90.68
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   NaNi
_chemical_formula_sum   'Na2 Ni2'
_cell_volume   77.97
_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
  Na  Na0  2  0.22  0.61  0.55  1.0
  Ni  Ni1  2  0.33  0.61  0.35  1.0

Na Na Ni Ni
Na Na Ni Ni 0 1 o o o 0 1 + o o 0 3 - o o 0 3 o o o 0 2 o o o 1 2 - o o 1 2 o o o 1 3 - o o 