data_Si2SbPb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   5.07
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2SbPb
_chemical_formula_sum   'Si2 Sb1 Pb1'
_cell_volume   92.15
_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  Si2  1  0.79  0.79  0.79  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0
  Sb  Sb1  1  0.58  0.58  0.58  1.0
  Pb  Pb0  1  0.38  0.38  0.38  1.0

data_Si2SbPb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   12.42
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Si2SbPb
_chemical_formula_sum   'Si6 Sb3 Pb3'
_cell_volume   276.45
_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
  Si  Si0  3  0.0  0.0  0.0  1.0
  Si  Si1  3  0.0  0.0  0.21  1.0
  Sb  Sb2  3  0.0  0.0  0.42  1.0
  Pb  Pb3  3  0.0  0.0  0.62  1.0

Si Si Sb Pb
Si Si Sb Pb 0 1 + o + 0 1 o + + 0 1 + + o 0 1 + + + 0 2 o o o 0 2 o o + 0 2 + o o 0 2 o + o 0 3 o o + 0 3 o + o 0 3 + o o 1 2 - - o 1 2 - o - 1 2 o - - 1 3 - o o 1 3 o - o 1 3 o o - 2 3 o o o 2 3 o o + 2 3 + o o 2 3 o + o 
PbSi2Sb crystallizes in the trigonal R3m space group. Pb(1) is bonded in a 10-coordinate geometry to three equivalent Si(1), three equivalent Si(2), and four equivalent Sb(1) atoms. All Pb(1)-Si(1) bond lengths are 3.10 Å. All Pb(1)-Si(2) bond lengths are 2.98 Å. There is one shorter (2.58 Å) and three longer (3.32 Å) Pb(1)-Sb(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to three equivalent Pb(1), one Si(2), and one Sb(1) atom. The Si(1)-Si(2) bond length is 2.58 Å. The Si(1)-Sb(1) bond length is 2.58 Å. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to three equivalent Pb(1), one Si(1), and three equivalent Sb(1) atoms. All Si(2)-Sb(1) bond lengths are 3.10 Å. Sb(1) is bonded in a distorted linear geometry to four equivalent Pb(1), one Si(1), and three equivalent Si(2) atoms.