data_Be4PbSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.97
_cell_length_b   4.97
_cell_length_c   4.97
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be4PbSe
_chemical_formula_sum   'Be4 Pb1 Se1'
_cell_volume   86.94
_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
  Be  Be0  1  0.39  0.39  0.64  1.0
  Be  Be1  1  0.39  0.64  0.39  1.0
  Be  Be2  1  0.64  0.39  0.39  1.0
  Be  Be3  1  0.64  0.64  0.64  1.0
  Pb  Pb4  1  0.27  0.27  0.27  1.0
  Se  Se5  1  0.0  0.0  0.0  1.0

data_Be4PbSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.97
_cell_length_b   4.97
_cell_length_c   12.18
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Be4PbSe
_chemical_formula_sum   'Be12 Pb3 Se3'
_cell_volume   260.83
_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
  Be  Be0  9  0.08  0.17  0.53  1.0
  Be  Be1  3  0.0  0.0  0.36  1.0
  Pb  Pb2  3  0.0  0.0  0.73  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Be Be Be Be Pb Se
Be4PbSe crystallizes in the trigonal R3m space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 6-coordinate geometry to one Be(2), two equivalent Be(1), two equivalent Pb(1), and one Se(1) atom. The Be(1)-Be(2) bond length is 2.16 Å. Both Be(1)-Be(1) bond lengths are 1.25 Å. There is one shorter (2.54 Å) and one longer (2.69 Å) Be(1)-Pb(1) bond length. The Be(1)-Se(1) bond length is 2.75 Å. In the second Be site, Be(2) is bonded in a 9-coordinate geometry to three equivalent Be(1), three equivalent Pb(1), and three equivalent Se(1) atoms. All Be(2)-Pb(1) bond lengths are 2.90 Å. All Be(2)-Se(1) bond lengths are 2.89 Å. Pb(1) is bonded in a 12-coordinate geometry to three equivalent Be(2), six equivalent Be(1), and three equivalent Se(1) atoms. All Pb(1)-Se(1) bond lengths are 2.96 Å. Se(1) is bonded in a 9-coordinate geometry to three equivalent Be(1), three equivalent Be(2), and three equivalent Pb(1) atoms.