data_YNb2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.17
_cell_length_b   9.17
_cell_length_c   9.17
_cell_angle_alpha   20.72
_cell_angle_beta   20.72
_cell_angle_gamma   20.72
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YNb2Se
_chemical_formula_sum   'Y1 Nb2 Se1'
_cell_volume   84.46
_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  0.0  0.0  0.45  1.0
  Nb  Nb0  1  0.0  0.0  0.08  1.0
  Nb  Nb1  1  0.0  0.0  0.83  1.0
  Se  Se2  1  0.0  0.0  0.0  1.0

data_YNb2Se
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.71
_cell_length_b   3.3
_cell_length_c   9.17
_cell_angle_alpha   90.0
_cell_angle_beta   101.99
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   YNb2Se
_chemical_formula_sum   'Y2 Nb4 Se2'
_cell_volume   168.92
_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
  Y  Y0  2  0.0  0.0  0.55  1.0
  Nb  Nb1  2  0.0  0.0  0.17  1.0
  Nb  Nb2  2  0.0  0.0  0.92  1.0
  Se  Se3  2  0.0  0.0  0.0  1.0

Y Nb Nb Se
Y Nb Nb Se 0 0 o + - 0 0 + - o 0 0 + o - 0 1 o o o 0 2 o o o 1 3 o o o 2 3 o o + 
YNb2Se crystallizes in the monoclinic Cm space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to six Y(1,1); one Nb(1); and one Nb(2) atom to form a mixture of distorted corner and edge-sharing YY6Nb2 hexagonal bipyramids. All Y(1)-Y(1,1) bond lengths are 3.30 Å. The Y(1)-Nb(1) bond length is 3.44 Å. The Y(1)-Nb(2) bond length is 3.44 Å. In the second Y site, Y(1) is bonded to six Y(1,1); one Nb(1); and one Nb(2) atom to form a mixture of distorted corner and edge-sharing YY6Nb2 hexagonal bipyramids. Both Y(1)-Y(1) bond lengths are 3.30 Å. The Y(1)-Nb(1) bond length is 3.44 Å. The Y(1)-Nb(2) bond length is 3.44 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a single-bond geometry to one Y(1) and one Se(1) atom. The Nb(1)-Se(1) bond length is 0.71 Å. In the second Nb site, Nb(2) is bonded in a single-bond geometry to one Y(1) and one Se(1) atom. The Nb(2)-Se(1) bond length is 1.58 Å. Se(1) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom.