data_MnBe2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.09
_cell_length_b   3.09
_cell_length_c   4.63
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MnBe2Se
_chemical_formula_sum   'Mn1 Be2 Se1'
_cell_volume   44.04
_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  Mn2  1  0.0  0.0  0.0  1.0
  Be  Be0  1  0.54  0.54  0.58  1.0
  Be  Be1  1  0.54  0.54  0.04  1.0
  Se  Se3  1  0.0  0.0  0.31  1.0

data_MnBe2Se
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.36
_cell_length_b   4.36
_cell_length_c   4.63
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MnBe2Se
_chemical_formula_sum   'Mn2 Be4 Se2'
_cell_volume   88.08
_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
  Mn  Mn0  2  0.0  0.0  0.0  1.0
  Be  Be1  2  0.04  0.5  0.04  1.0
  Be  Be2  2  0.04  0.5  0.58  1.0
  Se  Se3  2  0.0  0.0  0.31  1.0

Mn Be Be Se
Mn Be Be Se 0 3 o o o 0 1 - - - 0 2 o o o 0 2 o - o 0 2 - o o 0 2 - - o 1 3 o o o 1 3 o + o 1 3 + o o 1 3 + + o 1 2 o o o 1 2 o o + 2 3 o + o 2 3 + o o 2 3 + + o 
Be2MnSe crystallizes in the monoclinic Cm space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 5-coordinate geometry to two equivalent Be(2) and four equivalent Se(1) atoms. There is one shorter (2.12 Å) and one longer (2.51 Å) Be(1)-Be(2) bond length. There are a spread of Be(1)-Se(1) bond distances ranging from 2.36-2.68 Å. In the second Be site, Be(2) is bonded in a 10-coordinate geometry to two equivalent Be(1), four equivalent Mn(1), and four equivalent Se(1) atoms. There are a spread of Be(2)-Mn(1) bond distances ranging from 2.01-2.38 Å. There are a spread of Be(2)-Se(1) bond distances ranging from 2.36-2.68 Å. Mn(1) is bonded in a single-bond geometry to four equivalent Be(2) and one Se(1) atom. The Mn(1)-Se(1) bond length is 1.45 Å. Se(1) is bonded in a distorted single-bond geometry to four equivalent Be(1), four equivalent Be(2), and one Mn(1) atom.