data_Be4BiSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   5.0
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be4BiSe
_chemical_formula_sum   'Be4 Bi1 Se1'
_cell_volume   88.29
_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  0.42  0.42  0.65  1.0
  Be  Be1  1  0.42  0.65  0.42  1.0
  Be  Be2  1  0.65  0.42  0.42  1.0
  Be  Be3  1  0.65  0.65  0.65  1.0
  Bi  Bi4  1  0.3  0.3  0.3  1.0
  Se  Se5  1  0.0  0.0  0.0  1.0

data_Be4BiSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   12.24
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Be4BiSe
_chemical_formula_sum   'Be12 Bi3 Se3'
_cell_volume   264.87
_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  0.15  0.5  1.0
  Be  Be1  3  0.0  0.0  0.35  1.0
  Bi  Bi2  3  0.0  0.0  0.7  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Be Be Be Be Bi Se
Be Be Be Be Bi Se 0 2 o o o 0 1 o o o 0 3 o o o 0 4 o o + 0 4 o o o 0 5 + o + 0 5 o + + 0 5 o o + 1 2 o o o 1 3 o o o 1 4 o + o 1 4 o o o 1 5 + + o 1 5 o + + 1 5 o + o 2 3 o o o 2 4 + o o 2 4 o o o 2 5 + + o 2 5 + o + 2 5 + o o 3 4 + o o 3 4 o + o 3 4 o o + 3 5 + + o 3 5 + o + 3 5 o + + 4 5 o o + 4 5 o + o 4 5 + o o 
Be4BiSe crystallizes in the trigonal R3m space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 2-coordinate geometry to one Be(2), two equivalent Be(1), two equivalent Bi(1), and one Se(1) atom. The Be(1)-Be(2) bond length is 2.01 Å. Both Be(1)-Be(1) bond lengths are 1.16 Å. There is one shorter (2.47 Å) and one longer (2.80 Å) Be(1)-Bi(1) bond length. The Be(1)-Se(1) bond length is 2.98 Å. In the second Be site, Be(2) is bonded in a 9-coordinate geometry to three equivalent Be(1), three equivalent Bi(1), and three equivalent Se(1) atoms. All Be(2)-Bi(1) bond lengths are 2.89 Å. All Be(2)-Se(1) bond lengths are 2.89 Å. Bi(1) is bonded to three equivalent Be(2), six equivalent Be(1), and three equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing BiBe9Se3 cuboctahedra. All Bi(1)-Se(1) bond lengths are 2.91 Å. Se(1) is bonded in a 9-coordinate geometry to three equivalent Be(1), three equivalent Be(2), and three equivalent Bi(1) atoms.