data_Si4WSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   5.04
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si4WSe
_chemical_formula_sum   'Si4 W1 Se1'
_cell_volume   90.41
_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
  Si  Si1  1  0.46  0.46  0.67  1.0
  Si  Si2  1  0.46  0.67  0.46  1.0
  Si  Si3  1  0.67  0.46  0.46  1.0
  Si  Si4  1  0.67  0.67  0.67  1.0
  W  W5  1  0.34  0.34  0.34  1.0
  Se  Se0  1  0.0  0.0  0.0  1.0

data_Si4WSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   12.34
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Si4WSe
_chemical_formula_sum   'Si12 W3 Se3'
_cell_volume   271.22
_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
  Si  Si0  9  0.07  0.14  0.47  1.0
  Si  Si1  3  0.0  0.0  0.33  1.0
  W  W2  3  0.0  0.0  0.66  1.0
  Se  Se3  3  0.0  0.0  -0.0  1.0

Si Si Si Si W Se
WSi4Se crystallizes in the trigonal R3m space group. W(1) is bonded to three equivalent Si(2), six equivalent Si(1), and three equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing WSi9Se3 cuboctahedra. All W(1)-Si(2) bond lengths are 2.91 Å. There are three shorter (2.35 Å) and three longer (2.95 Å) W(1)-Si(1) bond lengths. All W(1)-Se(1) bond lengths are 2.91 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 2-coordinate geometry to two equivalent W(1), one Si(2), and two equivalent Si(1) atoms. The Si(1)-Si(2) bond length is 1.81 Å. Both Si(1)-Si(1) bond lengths are 1.04 Å. In the second Si site, Si(2) is bonded in a distorted q6 geometry to three equivalent W(1), three equivalent Si(1), and three equivalent Se(1) atoms. All Si(2)-Se(1) bond lengths are 2.91 Å. Se(1) is bonded in a hexagonal planar geometry to three equivalent W(1) and three equivalent Si(2) atoms.