data_Ni3N
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.27
_cell_length_b   4.27
_cell_length_c   4.27
_cell_angle_alpha   133.81
_cell_angle_beta   133.81
_cell_angle_gamma   67.39
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ni3N
_chemical_formula_sum   'Ni3 N1'
_cell_volume   39.93
_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
  Ni  Ni1  1  0.0  0.0  0.55  1.0
  Ni  Ni2  1  0.0  0.68  0.78  1.0
  Ni  Ni3  1  0.68  0.0  0.78  1.0
  N  N0  1  0.0  0.0  0.0  1.0

data_Ni3N
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.74
_cell_length_b   4.74
_cell_length_c   4.27
_cell_angle_alpha   90.0
_cell_angle_beta   123.7
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ni3N
_chemical_formula_sum   'Ni6 N2'
_cell_volume   79.85
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Ni  Ni0  4  0.16  0.16  0.1  1.0
  Ni  Ni1  2  0.0  0.0  0.55  1.0
  N  N2  2  0.0  0.0  0.0  1.0

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