data_BeSbSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.35
_cell_length_b   7.35
_cell_length_c   7.35
_cell_angle_alpha   28.45
_cell_angle_beta   28.45
_cell_angle_gamma   28.45
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BeSbSe2
_chemical_formula_sum   'Be1 Sb1 Se2'
_cell_volume   79.55
_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  0.0  0.0  0.0  1.0
  Sb  Sb1  1  0.0  0.0  0.57  1.0
  Se  Se2  1  0.0  0.0  0.75  1.0
  Se  Se3  1  0.0  0.0  0.38  1.0

data_BeSbSe2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.25
_cell_length_b   3.61
_cell_length_c   7.35
_cell_angle_alpha   90.0
_cell_angle_beta   106.49
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BeSbSe2
_chemical_formula_sum   'Be2 Sb2 Se4'
_cell_volume   159.1
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.0  1.0
  Sb  Sb1  2  0.0  0.0  0.43  1.0
  Se  Se2  2  0.0  0.0  0.25  1.0
  Se  Se3  2  0.0  0.0  0.62  1.0

Be Sb Se Se
Be Sb Se Se 0 2 o o - 1 3 o o o 1 2 o o o 
BeSbSe2 is Indium-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two BeSbSe2 clusters. Be(1) is bonded in a distorted single-bond geometry to one Se(1) atom. The Be(1)-Se(1) bond length is 1.81 Å. Sb(1) is bonded in a linear geometry to one Se(1) and one Se(2) atom. The Sb(1)-Se(1) bond length is 1.37 Å. The Sb(1)-Se(2) bond length is 1.37 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a linear geometry to one Be(1) and one Sb(1) atom. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to one Sb(1) atom.