data_SiB2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.34
_cell_length_b   3.13
_cell_length_c   5.46
_cell_angle_alpha   90.0
_cell_angle_beta   96.35
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiB2Se
_chemical_formula_sum   'Si1 B2 Se1'
_cell_volume   56.6
_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  Si3  1  0.17  0.0  0.81  1.0
  B  B0  1  0.83  0.56  0.43  1.0
  B  B1  1  0.93  0.0  0.25  1.0
  Se  Se2  1  0.56  0.56  0.07  1.0

data_SiB2Se
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.13
_cell_length_b   3.34
_cell_length_c   5.46
_cell_angle_alpha   96.35
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiB2Se
_chemical_formula_sum   'Si1 B2 Se1'
_cell_volume   56.6
_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  Si0  1  0.0  0.83  0.19  1.0
  B  B1  1  0.0  0.07  0.75  1.0
  B  B2  1  0.44  0.17  0.57  1.0
  Se  Se3  1  0.44  0.44  0.93  1.0

Si B B Se
Si B B Se 0 1 - - o 0 1 - o o 0 3 - - + 0 3 o - + 0 3 o o + 0 2 - o + 1 3 o o o 1 2 o o o 1 2 o + o 2 3 o - o 2 3 o o o 
B2SiSe crystallizes in the triclinic P1 space group. There are two inequivalent B sites. In the first B site, B(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent B(2), one Si(1), and one Se(1) atom. There is one shorter (1.75 Å) and one longer (2.08 Å) B(1)-B(2) bond length. The B(1)-Si(1) bond length is 2.63 Å. The B(1)-Se(1) bond length is 2.10 Å. In the second B site, B(2) is bonded in a 6-coordinate geometry to two equivalent B(1), one Si(1), and three equivalent Se(1) atoms. The B(2)-Si(1) bond length is 2.58 Å. There are a spread of B(2)-Se(1) bond distances ranging from 2.01-2.78 Å. Si(1) is bonded in a 2-coordinate geometry to one B(1), one B(2), and two equivalent Se(1) atoms. There is one shorter (2.25 Å) and one longer (2.51 Å) Si(1)-Se(1) bond length. Se(1) is bonded in a 5-coordinate geometry to one B(1), three equivalent B(2), and two equivalent Si(1) atoms.