data_Ta2HgPb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.94
_cell_length_b   4.94
_cell_length_c   4.94
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2HgPb
_chemical_formula_sum   'Ta2 Hg1 Pb1'
_cell_volume   85.12
_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
  Ta  Ta2  1  0.0  0.0  0.0  1.0
  Ta  Ta3  1  0.75  0.75  0.75  1.0
  Hg  Hg0  1  0.49  0.49  0.49  1.0
  Pb  Pb1  1  0.24  0.24  0.24  1.0

data_Ta2HgPb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.94
_cell_length_b   4.94
_cell_length_c   12.09
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Ta2HgPb
_chemical_formula_sum   'Ta6 Hg3 Pb3'
_cell_volume   255.35
_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
  Ta  Ta0  3  0.0  0.0  -0.0  1.0
  Ta  Ta1  3  0.0  0.0  0.25  1.0
  Hg  Hg2  3  0.0  0.0  0.51  1.0
  Pb  Pb3  3  0.0  0.0  0.76  1.0

Ta Ta Hg Pb
Ta2HgPb crystallizes in the trigonal R3m space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to four equivalent Ta(2) and four equivalent Pb(1) atoms to form distorted TaTa4Pb4 tetrahedra that share corners with twelve equivalent Ta(2)Ta4Hg4Pb6 tetrahedra, edges with twelve equivalent Ta(1)Ta4Pb4 tetrahedra, and faces with four equivalent Ta(2)Ta4Hg4Pb6 tetrahedra. There are three shorter (3.01 Å) and one longer (3.08 Å) Ta(1)-Ta(2) bond length. There is one shorter (2.87 Å) and three longer (3.08 Å) Ta(1)-Pb(1) bond lengths. In the second Ta site, Ta(2) is bonded to four equivalent Ta(1), four equivalent Hg(1), and six equivalent Pb(1) atoms to form distorted TaTa4Hg4Pb6 tetrahedra that share corners with six equivalent Ta(2)Ta4Hg4Pb6 tetrahedra, corners with twelve equivalent Ta(1)Ta4Pb4 tetrahedra, faces with four equivalent Ta(1)Ta4Pb4 tetrahedra, and faces with twelve equivalent Ta(2)Ta4Hg4Pb6 tetrahedra. There are three shorter (3.01 Å) and one longer (3.08 Å) Ta(2)-Hg(1) bond length. There are three shorter (3.43 Å) and three longer (3.55 Å) Ta(2)-Pb(1) bond lengths. Hg(1) is bonded in a distorted body-centered cubic geometry to four equivalent Ta(2) and four equivalent Pb(1) atoms. There are three shorter (3.01 Å) and one longer (3.08 Å) Hg(1)-Pb(1) bond length. Pb(1) is bonded in a 8-coordinate geometry to four equivalent Ta(1), six equivalent Ta(2), and four equivalent Hg(1) atoms.