data_Ir4C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.53
_cell_length_b   4.53
_cell_length_c   4.53
_cell_angle_alpha   109.47
_cell_angle_beta   109.47
_cell_angle_gamma   109.47
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ir4C
_chemical_formula_sum   'Ir4 C1'
_cell_volume   71.51
_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
  Ir  Ir1  1  0.31  0.31  0.69  1.0
  Ir  Ir2  1  0.31  0.31  0.31  1.0
  Ir  Ir3  1  0.31  0.69  0.31  1.0
  Ir  Ir4  1  0.69  0.31  0.31  1.0
  C  C0  1  0.0  0.0  0.0  1.0

data_Ir4C
_symmetry_space_group_name_H-M   R3m
_cell_length_a   7.4
_cell_length_b   7.4
_cell_length_c   4.53
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Ir4C
_chemical_formula_sum   'Ir12 C3'
_cell_volume   214.52
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+2/3, y+1/3, z+1/3'
  8  '-y+2/3, x-y+1/3, z+1/3'
  9  '-x+y+2/3, -x+1/3, z+1/3'
  10  '-y+2/3, -x+1/3, z+1/3'
  11  '-x+y+2/3, y+1/3, z+1/3'
  12  'x+2/3, x-y+1/3, z+1/3'
  13  'x+1/3, y+2/3, z+2/3'
  14  '-y+1/3, x-y+2/3, z+2/3'
  15  '-x+y+1/3, -x+2/3, z+2/3'
  16  '-y+1/3, -x+2/3, z+2/3'
  17  '-x+y+1/3, y+2/3, z+2/3'
  18  'x+1/3, x-y+2/3, z+2/3'
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
  Ir  Ir0  9  0.2  0.41  0.1  1.0
  Ir  Ir1  3  0.0  0.0  0.31  1.0
  C  C2  3  0.0  0.0  0.0  1.0

Ir Ir Ir Ir C
Ir Ir Ir Ir C 0 1 o o o 1 4 o o o 1 2 o o o 1 3 o o o 
Ir4C crystallizes in the trigonal R3m space group. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 2-coordinate geometry to one Ir(2) and one C(1) atom. The Ir(1)-Ir(2) bond length is 1.74 Å. The Ir(1)-C(1) bond length is 2.67 Å. In the second Ir site, Ir(2) is bonded in a distorted single-bond geometry to three equivalent Ir(1) and one C(1) atom. The Ir(2)-C(1) bond length is 1.39 Å. C(1) is bonded in a single-bond geometry to one Ir(2) and three equivalent Ir(1) atoms.