data_Na3CI
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.06
_cell_length_b   5.06
_cell_length_c   5.06
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na3CI
_chemical_formula_sum   'Na3 C1 I1'
_cell_volume   129.59
_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
  Na  Na1  1  0.0  0.53  0.0  1.0
  Na  Na2  1  0.0  0.0  0.53  1.0
  Na  Na3  1  0.53  0.0  0.0  1.0
  C  C4  1  0.0  0.0  0.0  1.0
  I  I0  1  0.53  0.53  0.53  1.0

data_Na3CI
_symmetry_space_group_name_H-M   R3m
_cell_length_a   7.16
_cell_length_b   7.16
_cell_length_c   8.76
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na3CI
_chemical_formula_sum   'Na9 C3 I3'
_cell_volume   388.77
_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+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Na  Na0  9  0.02  0.51  0.51  1.0
  C  C1  3  0.0  0.0  0.0  1.0
  I  I2  3  0.0  0.0  0.53  1.0

Na Na Na C I
Na Na Na C I 0 3 o o o 0 3 o + o 0 4 o o o 0 4 o o - 0 4 - o o 0 4 - o - 1 3 o o o 1 3 o o + 1 4 o o o 1 4 o - o 1 4 - o o 1 4 - - o 2 3 o o o 2 3 + o o 2 4 o o o 2 4 o o - 2 4 o - o 2 4 o - - 3 4 - - - 
Na3CI is (Cubic) Perovskite structured and crystallizes in the trigonal R3m space group. Na(1) is bonded in a 2-coordinate geometry to two equivalent C(1) and three equivalent I(1) atoms. There is one shorter (2.38 Å) and one longer (2.68 Å) Na(1)-C(1) bond length. There is one shorter (3.36 Å) and two longer (3.58 Å) Na(1)-I(1) bond lengths. C(1) is bonded to six equivalent Na(1) atoms to form CNa6 octahedra that share corners with six equivalent C(1)Na6 octahedra, edges with three equivalent I(1)Na9 cuboctahedra, and faces with four equivalent I(1)Na9 cuboctahedra. The corner-sharing octahedra are not tilted. I(1) is bonded to nine equivalent Na(1) atoms to form distorted INa9 cuboctahedra that share corners with six equivalent I(1)Na9 cuboctahedra, edges with six equivalent I(1)Na9 cuboctahedra, edges with three equivalent C(1)Na6 octahedra, and faces with four equivalent C(1)Na6 octahedra.