data_SrTa2Pb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   5.18
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrTa2Pb
_chemical_formula_sum   'Sr1 Ta2 Pb1'
_cell_volume   98.1
_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
  Sr  Sr1  1  0.0  0.0  0.0  1.0
  Ta  Ta2  1  0.83  0.83  0.83  1.0
  Ta  Ta3  1  0.49  0.49  0.49  1.0
  Pb  Pb0  1  0.66  0.66  0.66  1.0

data_SrTa2Pb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   12.68
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrTa2Pb
_chemical_formula_sum   'Sr3 Ta6 Pb3'
_cell_volume   294.29
_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
  Sr  Sr0  3  0.0  0.0  0.0  1.0
  Ta  Ta1  3  0.0  0.0  0.17  1.0
  Ta  Ta2  3  0.0  0.0  0.51  1.0
  Pb  Pb3  3  0.0  0.0  0.34  1.0

Sr Ta Ta Pb
Sr Ta Ta Pb 0 1 - - - 1 3 o o o 2 3 o o o 
SrTa2Pb crystallizes in the trigonal R3m space group. Sr(1) is bonded to one Ta(1) and three equivalent Pb(1) atoms to form distorted SrTaPb3 trigonal pyramids that share  a cornercorner with one Pb(1)Sr3Ta2 trigonal bipyramid and corners with six equivalent Sr(1)TaPb3 trigonal pyramids. The Sr(1)-Ta(1) bond length is 2.15 Å. All Sr(1)-Pb(1) bond lengths are 2.99 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a linear geometry to one Sr(1) and one Pb(1) atom. The Ta(1)-Pb(1) bond length is 2.15 Å. In the second Ta site, Ta(2) is bonded in a single-bond geometry to one Pb(1) atom. The Ta(2)-Pb(1) bond length is 2.15 Å. Pb(1) is bonded to three equivalent Sr(1), one Ta(1), and one Ta(2) atom to form distorted PbSr3Ta2 trigonal bipyramids that share corners with six equivalent Pb(1)Sr3Ta2 trigonal bipyramids and  a cornercorner with one Sr(1)TaPb3 trigonal pyramid.