data_SrPbSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.02
_cell_length_b   6.02
_cell_length_c   6.02
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrPbSe4
_chemical_formula_sum   'Sr1 Pb1 Se4'
_cell_volume   154.18
_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  Sr5  1  0.0  0.0  0.0  1.0
  Pb  Pb0  1  0.13  0.13  0.13  1.0
  Se  Se1  1  0.19  0.19  0.32  1.0
  Se  Se2  1  0.19  0.32  0.19  1.0
  Se  Se3  1  0.32  0.19  0.19  1.0
  Se  Se4  1  0.32  0.32  0.32  1.0

data_SrPbSe4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.02
_cell_length_b   6.02
_cell_length_c   14.74
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrPbSe4
_chemical_formula_sum   'Sr3 Pb3 Se12'
_cell_volume   462.54
_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
  Pb  Pb1  3  0.0  0.0  0.87  1.0
  Se  Se2  9  0.04  0.09  0.77  1.0
  Se  Se3  3  0.0  0.0  0.68  1.0

Sr Pb Se Se Se Se
SrPbSe4 crystallizes in the trigonal R3m space group. Sr(1) is bonded in a distorted single-bond geometry to one Pb(1), three equivalent Se(1), and three equivalent Se(2) atoms. The Sr(1)-Pb(1) bond length is 1.89 Å. All Sr(1)-Se(1) bond lengths are 3.36 Å. All Sr(1)-Se(2) bond lengths are 3.48 Å. Pb(1) is bonded in a single-bond geometry to one Sr(1) and three equivalent Se(1) atoms. All Pb(1)-Se(1) bond lengths are 1.63 Å. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Sr(1) and three equivalent Se(1) atoms. All Se(2)-Se(1) bond lengths are 1.35 Å. In the second Se site, Se(1) is bonded in a distorted pentagonal planar geometry to one Sr(1), one Pb(1), one Se(2), and two equivalent Se(1) atoms. Both Se(1)-Se(1) bond lengths are 0.78 Å.