data_Be4NbSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.59
_cell_length_b   4.59
_cell_length_c   4.59
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be4NbSe
_chemical_formula_sum   'Be4 Nb1 Se1'
_cell_volume   68.41
_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  0.03  0.03  0.46  1.0
  Be  Be1  1  0.03  0.46  0.03  1.0
  Be  Be2  1  0.46  0.03  0.03  1.0
  Be  Be3  1  0.46  0.46  0.46  1.0
  Nb  Nb4  1  0.87  0.87  0.87  1.0
  Se  Se5  1  0.0  0.0  0.0  1.0

data_Be4NbSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.59
_cell_length_b   4.59
_cell_length_c   11.25
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Be4NbSe
_chemical_formula_sum   'Be12 Nb3 Se3'
_cell_volume   205.24
_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  9  0.04  0.52  0.49  1.0
  Be  Be1  3  0.0  0.0  0.54  1.0
  Nb  Nb2  3  0.0  0.0  0.13  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Be Be Be Be Nb Se
Be Be Be Be Nb Se 0 4 - - o 0 3 o - o 0 3 - o o 1 4 - o - 1 3 o o - 1 3 - o o 2 4 o - - 2 3 o o - 2 3 o - o 3 4 - o o 3 4 o - o 3 4 o o - 4 5 + + + 
Be4NbSe crystallizes in the trigonal R3m space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 7-coordinate geometry to two equivalent Be(1), two equivalent Be(2), one Nb(1), and two equivalent Se(1) atoms. Both Be(1)-Be(1) bond lengths are 1.99 Å. Both Be(1)-Be(2) bond lengths are 2.35 Å. The Be(1)-Nb(1) bond length is 1.54 Å. There is one shorter (2.27 Å) and one longer (2.34 Å) Be(1)-Se(1) bond length. In the second Be site, Be(2) is bonded in a distorted hexagonal planar geometry to six equivalent Be(1) atoms. Nb(1) is bonded in a distorted single-bond geometry to three equivalent Be(1) and one Se(1) atom. The Nb(1)-Se(1) bond length is 1.47 Å. Se(1) is bonded in a distorted single-bond geometry to six equivalent Be(1) and one Nb(1) atom.