data_NaCu3I
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.14
_cell_length_b   5.14
_cell_length_c   5.14
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaCu3I
_chemical_formula_sum   'Na1 Cu3 I1'
_cell_volume   135.68
_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  0.0  0.0  1.0
  Cu  Cu2  1  0.57  0.0  0.57  1.0
  Cu  Cu3  1  0.57  0.57  0.0  1.0
  Cu  Cu4  1  0.0  0.57  0.57  1.0
  I  I0  1  0.57  0.57  0.57  1.0

data_NaCu3I
_symmetry_space_group_name_H-M   R3m
_cell_length_a   7.27
_cell_length_b   7.27
_cell_length_c   8.9
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaCu3I
_chemical_formula_sum   'Na3 Cu9 I3'
_cell_volume   407.03
_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  3  0.0  0.0  0.0  1.0
  Cu  Cu1  9  0.19  0.38  0.38  1.0
  I  I2  3  0.0  0.0  0.57  1.0

Na Cu Cu Cu I
NaCu3I crystallizes in the trigonal R3m space group. Na(1) is bonded in a 9-coordinate geometry to nine equivalent Cu(1) atoms. There are three shorter (3.13 Å) and six longer (3.67 Å) Na(1)-Cu(1) bond lengths. Cu(1) is bonded in a 1-coordinate geometry to three equivalent Na(1) and two equivalent I(1) atoms. There is one shorter (2.21 Å) and one longer (2.92 Å) Cu(1)-I(1) bond length. I(1) is bonded to six equivalent Cu(1) atoms to form corner-sharing ICu6 octahedra. The corner-sharing octahedra are not tilted.