data_LaSiPb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.03
_cell_length_b   5.03
_cell_length_c   5.03
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   LaSiPb
_chemical_formula_sum   'La1 Si1 Pb1'
_cell_volume   89.88
_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
  La  La0  1  0.33  0.33  0.33  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0
  Pb  Pb1  1  0.78  0.78  0.78  1.0

data_LaSiPb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.03
_cell_length_b   5.03
_cell_length_c   12.32
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   LaSiPb
_chemical_formula_sum   'La3 Si3 Pb3'
_cell_volume   269.64
_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
  La  La0  3  0.0  0.0  0.67  1.0
  Si  Si1  3  0.0  0.0  -0.0  1.0
  Pb  Pb2  3  0.0  0.0  0.22  1.0

La Si Pb
La Si Pb 0 1 o o + 0 1 o + o 0 1 + o o 0 2 - o o 0 2 o - o 0 2 o o - 1 2 - - - 1 2 - - o 1 2 o - - 1 2 - o - 
LaPbSi is half-Heusler structured and crystallizes in the trigonal R3m space group. La(1) is bonded in a distorted hexagonal planar geometry to six equivalent Pb(1) and three equivalent Si(1) atoms. There are three shorter (3.21 Å) and three longer (3.99 Å) La(1)-Pb(1) bond lengths. All La(1)-Si(1) bond lengths are 2.90 Å. Pb(1) is bonded in a 10-coordinate geometry to six equivalent La(1) and four equivalent Si(1) atoms. There is one shorter (2.74 Å) and three longer (3.21 Å) Pb(1)-Si(1) bond lengths. Si(1) is bonded to three equivalent La(1) and four equivalent Pb(1) atoms to form a mixture of distorted corner and edge-sharing SiLa3Pb4 trigonal pyramids.