data_MnBeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.34
_cell_length_b   3.36
_cell_length_c   6.54
_cell_angle_alpha   90.0
_cell_angle_beta   92.21
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MnBeSe2
_chemical_formula_sum   'Mn1 Be1 Se2'
_cell_volume   73.3
_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
  Mn  Mn1  1  0.26  0.68  0.09  1.0
  Be  Be0  1  0.93  0.0  0.08  1.0
  Se  Se2  1  0.26  0.0  0.74  1.0
  Se  Se3  1  0.93  0.68  0.43  1.0

data_MnBeSe2
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.34
_cell_length_b   3.36
_cell_length_c   6.54
_cell_angle_alpha   90.0
_cell_angle_beta   92.21
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MnBeSe2
_chemical_formula_sum   'Mn1 Be1 Se2'
_cell_volume   73.3
_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
  Mn  Mn0  1  0.26  0.68  0.09  1.0
  Be  Be1  1  0.93  0.0  0.08  1.0
  Se  Se2  1  0.26  0.0  0.74  1.0
  Se  Se3  1  0.93  0.68  0.43  1.0

Mn Be Se Se
Mn Be Se Se 0 1 - + o 0 2 o + - 0 3 - o o 1 2 + o - 1 3 o - o 2 3 - - o 
BeMnSe2 crystallizes in the triclinic P1 space group. Be(1) is bonded in a 5-coordinate geometry to three equivalent Mn(1), one Se(1), and one Se(2) atom. There are a spread of Be(1)-Mn(1) bond distances ranging from 1.54-2.52 Å. The Be(1)-Se(1) bond length is 2.49 Å. The Be(1)-Se(2) bond length is 2.55 Å. Mn(1) is bonded in a 3-coordinate geometry to three equivalent Be(1), two equivalent Se(1), and two equivalent Se(2) atoms. There is one shorter (2.52 Å) and one longer (3.22 Å) Mn(1)-Se(1) bond length. There is one shorter (2.52 Å) and one longer (3.10 Å) Mn(1)-Se(2) bond length. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Mn(1), and one Se(2) atom. The Se(1)-Se(2) bond length is 2.52 Å. In the second Se site, Se(2) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Mn(1), and one Se(1) atom.