data_YBSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.89
_cell_length_b   4.89
_cell_length_c   4.89
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YBSe2
_chemical_formula_sum   'Y1 B1 Se2'
_cell_volume   82.63
_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
  Y  Y3  1  0.46  0.46  0.46  1.0
  B  B0  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.19  0.19  0.19  1.0
  Se  Se2  1  0.73  0.73  0.73  1.0

data_YBSe2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.89
_cell_length_b   4.89
_cell_length_c   11.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   YBSe2
_chemical_formula_sum   'Y3 B3 Se6'
_cell_volume   247.88
_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
  Y  Y0  3  0.0  0.0  0.54  1.0
  B  B1  3  0.0  0.0  0.0  1.0
  Se  Se2  3  0.0  0.0  0.27  1.0
  Se  Se3  3  0.0  0.0  0.81  1.0

Y B Se Se
Y B Se Se 0 2 o o o 0 2 o o + 0 2 o + o 0 2 + o o 0 1 o o + 0 1 o + o 0 1 + o o 0 3 - o o 0 3 o - o 0 3 o o - 0 3 o o o 1 2 o o o 1 3 o - - 1 3 - o - 1 3 - - o 1 3 - - - 2 3 o - - 2 3 - o - 2 3 - - o 
YBSe2 is Heusler structured and crystallizes in the trigonal R3m space group. Y(1) is bonded in a 11-coordinate geometry to three equivalent B(1), four equivalent Se(1), and four equivalent Se(2) atoms. All Y(1)-B(1) bond lengths are 3.19 Å. There are three shorter (2.92 Å) and one longer (3.25 Å) Y(1)-Se(1) bond length. There are three shorter (2.92 Å) and one longer (3.25 Å) Y(1)-Se(2) bond length. B(1) is bonded in a single-bond geometry to three equivalent Y(1) and one Se(1) atom. The B(1)-Se(1) bond length is 2.22 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to four equivalent Y(1) and one B(1) atom. In the second Se site, Se(2) is bonded to four equivalent Y(1) atoms to form corner-sharing SeY4 tetrahedra.