data_Si2NiAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.67
_cell_length_b   4.67
_cell_length_c   4.69
_cell_angle_alpha   100.15
_cell_angle_beta   100.15
_cell_angle_gamma   34.25
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2NiAs
_chemical_formula_sum   'Si2 Ni1 As1'
_cell_volume   56.74
_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
  Si  Si2  1  0.05  0.0  0.59  1.0
  Si  Si3  1  0.48  0.0  0.13  1.0
  Ni  Ni1  1  0.59  0.0  0.47  1.0
  As  As0  1  0.05  0.0  0.34  1.0

data_Si2NiAs
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.75
_cell_length_b   4.67
_cell_length_c   4.69
_cell_angle_alpha   100.15
_cell_angle_beta   90.0
_cell_angle_gamma   107.13
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2NiAs
_chemical_formula_sum   'Si2 Ni1 As1'
_cell_volume   56.74
_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
  Si  Si0  1  0.0  0.52  0.87  1.0
  Si  Si1  1  0.0  0.95  0.41  1.0
  Ni  Ni2  1  0.0  0.41  0.53  1.0
  As  As3  1  0.0  0.95  0.66  1.0

Si Si Ni As
Si Si Ni As 0 3 o o o 1 2 o o o 