data_SiIr3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.64
_cell_length_b   4.64
_cell_length_c   4.64
_cell_angle_alpha   130.45
_cell_angle_beta   130.45
_cell_angle_gamma   72.68
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiIr3
_chemical_formula_sum   'Si1 Ir3'
_cell_volume   56.45
_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  Si3  1  0.0  0.0  0.0  1.0
  Ir  Ir0  1  0.94  0.0  0.87  1.0
  Ir  Ir1  1  0.0  0.0  0.74  1.0
  Ir  Ir2  1  0.0  0.94  0.87  1.0

data_SiIr3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.5
_cell_length_b   5.5
_cell_length_c   4.64
_cell_angle_alpha   90.0
_cell_angle_beta   126.34
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   SiIr3
_chemical_formula_sum   'Si2 Ir6'
_cell_volume   112.9
_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
  Si  Si0  2  0.0  0.0  0.0  1.0
  Ir  Ir1  4  0.1  0.03  0.08  1.0
  Ir  Ir2  2  0.26  0.0  0.26  1.0

Si Ir Ir Ir
Si Ir Ir Ir 0 1 - o - 0 3 o - - 1 3 + - o 1 2 + o o 2 3 o - o 