data_CrSeBr2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   5.0
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CrSeBr2
_chemical_formula_sum   'Cr1 Se1 Br2'
_cell_volume   88.2
_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
  Cr  Cr2  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.3  0.3  0.3  1.0
  Br  Br0  1  0.53  0.53  0.53  1.0
  Br  Br1  1  0.77  0.77  0.77  1.0

data_CrSeBr2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   12.24
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CrSeBr2
_chemical_formula_sum   'Cr3 Se3 Br6'
_cell_volume   264.61
_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
  Cr  Cr0  3  0.0  0.0  0.0  1.0
  Se  Se1  3  0.0  0.0  0.7  1.0
  Br  Br2  3  0.0  0.0  0.23  1.0
  Br  Br3  3  0.0  0.0  0.47  1.0

Cr Se Br Br
Cr Se Br Br 0 3 - - - 0 3 - - o 0 3 o - - 0 3 - o - 0 2 - - o 0 2 - o - 0 2 o - - 0 1 - o o 0 1 o - o 0 1 o o - 1 2 o - o 1 2 - o o 1 2 o o - 1 2 o o o 1 3 - o o 1 3 o - o 1 3 o o - 2 3 o - o 2 3 - o o 2 3 o o - 2 3 o o o 
CrSeBr2 crystallizes in the trigonal R3m space group. Cr(1) is bonded in a 7-coordinate geometry to three equivalent Se(1) and four equivalent Br(2) atoms. All Cr(1)-Se(1) bond lengths are 2.91 Å. There is one shorter (2.86 Å) and three longer (3.13 Å) Cr(1)-Br(2) bond lengths. Se(1) is bonded to three equivalent Cr(1) and one Br(1) atom to form distorted corner-sharing SeCr3Br trigonal pyramids. The Se(1)-Br(1) bond length is 2.86 Å. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a distorted single-bond geometry to one Se(1) atom. In the second Br site, Br(2) is bonded in a 4-coordinate geometry to four equivalent Cr(1) atoms.