data_BeCr4Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.76
_cell_length_b   4.76
_cell_length_c   4.76
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BeCr4Se
_chemical_formula_sum   'Be1 Cr4 Se1'
_cell_volume   76.36
_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
  Cr  Cr1  1  0.22  0.22  0.51  1.0
  Cr  Cr2  1  0.22  0.51  0.22  1.0
  Cr  Cr3  1  0.51  0.22  0.22  1.0
  Cr  Cr4  1  0.51  0.51  0.51  1.0
  Se  Se5  1  0.05  0.05  0.05  1.0

data_BeCr4Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.76
_cell_length_b   4.76
_cell_length_c   11.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   BeCr4Se
_chemical_formula_sum   'Be3 Cr12 Se3'
_cell_volume   229.08
_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  3  0.0  0.0  0.0  1.0
  Cr  Cr1  9  0.1  0.2  0.68  1.0
  Cr  Cr2  3  0.0  0.0  0.49  1.0
  Se  Se3  3  0.0  0.0  0.95  1.0

Be Cr Cr Cr Cr Se
BeCr4Se crystallizes in the trigonal R3m space group. Be(1) is bonded in a single-bond geometry to three equivalent Cr(1) and one Se(1) atom. All Be(1)-Cr(1) bond lengths are 1.95 Å. The Be(1)-Se(1) bond length is 0.59 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Cr(1), three equivalent Cr(2), and one Se(1) atom. Both Cr(1)-Cr(1) bond lengths are 1.40 Å. There is one shorter (2.42 Å) and two longer (2.93 Å) Cr(1)-Cr(2) bond lengths. The Cr(1)-Se(1) bond length is 2.09 Å. In the second Cr site, Cr(2) is bonded in a 12-coordinate geometry to nine equivalent Cr(1) and three equivalent Se(1) atoms. All Cr(2)-Se(1) bond lengths are 3.14 Å. Se(1) is bonded in a single-bond geometry to one Be(1), three equivalent Cr(1), and three equivalent Cr(2) atoms.