data_Zn3SiI
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.92
_cell_length_b   4.92
_cell_length_c   4.92
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Zn3SiI
_chemical_formula_sum   'Zn3 Si1 I1'
_cell_volume   119.06
_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
  Zn  Zn1  1  0.0  0.46  0.0  1.0
  Zn  Zn2  1  0.0  0.0  0.46  1.0
  Zn  Zn3  1  0.46  0.0  0.0  1.0
  Si  Si4  1  0.0  0.0  0.0  1.0
  I  I0  1  0.46  0.46  0.46  1.0

data_Zn3SiI
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.96
_cell_length_b   6.96
_cell_length_c   8.52
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Zn3SiI
_chemical_formula_sum   'Zn9 Si3 I3'
_cell_volume   357.18
_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
  Zn  Zn0  9  0.18  0.36  0.82  1.0
  Si  Si1  3  0.0  0.0  0.0  1.0
  I  I2  3  0.0  0.0  0.46  1.0

Zn Zn Zn Si I
Zn Zn Zn Si 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 o o o 
Zn3SiI is (Cubic) Perovskite structured and crystallizes in the trigonal R3m space group. Zn(1) is bonded in a distorted T-shaped geometry to two equivalent Si(1) and one I(1) atom. There is one shorter (2.26 Å) and one longer (2.66 Å) Zn(1)-Si(1) bond length. The Zn(1)-I(1) bond length is 3.20 Å. Si(1) is bonded to six equivalent Zn(1) atoms to form corner-sharing SiZn6 octahedra. The corner-sharing octahedra are not tilted. I(1) is bonded in a 3-coordinate geometry to three equivalent Zn(1) atoms.