data_BeB2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.93
_cell_length_b   3.93
_cell_length_c   3.93
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BeB2Se
_chemical_formula_sum   'Be1 B2 Se1'
_cell_volume   42.9
_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  Be2  1  0.0  0.0  0.0  1.0
  B  B0  1  0.78  0.78  0.78  1.0
  B  B1  1  0.39  0.39  0.39  1.0
  Se  Se3  1  0.17  0.17  0.17  1.0

data_BeB2Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   3.93
_cell_length_b   3.93
_cell_length_c   9.62
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   BeB2Se
_chemical_formula_sum   'Be3 B6 Se3'
_cell_volume   128.69
_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  3  0.0  0.0  0.0  1.0
  B  B1  3  0.0  0.0  0.22  1.0
  B  B2  3  0.0  0.0  0.61  1.0
  Se  Se3  3  0.0  0.0  0.83  1.0

Be B B Se
Be B B Se 0 3 o o o 0 1 - o - 0 1 o - - 0 1 - - o 0 1 - - - 0 2 o o - 0 2 o - o 0 2 - o o 1 2 o o + 1 2 o + o 1 2 + o o 1 3 o + + 1 3 + o + 1 3 + + o 2 3 o o o 2 3 o o + 2 3 + o o 2 3 o + o 
BeB2Se crystallizes in the trigonal R3m space group. Be(1) is bonded in a distorted single-bond geometry to one B(1), three equivalent B(2), and one Se(1) atom. The Be(1)-B(1) bond length is 2.13 Å. All Be(1)-B(2) bond lengths are 2.33 Å. The Be(1)-Se(1) bond length is 1.61 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 4-coordinate geometry to one Be(1), three equivalent B(2), and three equivalent Se(1) atoms. All B(1)-B(2) bond lengths are 2.33 Å. All B(1)-Se(1) bond lengths are 2.33 Å. In the second B site, B(2) is bonded in a 10-coordinate geometry to three equivalent Be(1), three equivalent B(1), and four equivalent Se(1) atoms. There is one shorter (2.13 Å) and three longer (2.51 Å) B(2)-Se(1) bond lengths. Se(1) is bonded in a distorted single-bond geometry to one Be(1), three equivalent B(1), and four equivalent B(2) atoms.