data_Y3Nb2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.76
_cell_length_b   12.76
_cell_length_c   12.76
_cell_angle_alpha   165.73
_cell_angle_beta   165.73
_cell_angle_gamma   20.24
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Y3Nb2
_chemical_formula_sum   'Y3 Nb2'
_cell_volume   126.26
_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  Y2  1  0.0  0.0  0.0  1.0
  Y  Y3  1  0.0  0.0  0.68  1.0
  Y  Y4  1  0.0  0.0  0.44  1.0
  Nb  Nb0  1  0.0  0.0  0.14  1.0
  Nb  Nb1  1  0.0  0.0  0.99  1.0

data_Y3Nb2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.48
_cell_length_b   4.48
_cell_length_c   12.76
_cell_angle_alpha   90.0
_cell_angle_beta   100.12
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Y3Nb2
_chemical_formula_sum   'Y6 Nb4'
_cell_volume   252.52
_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  0.0  1.0
  Y  Y1  2  0.0  0.0  0.32  1.0
  Y  Y2  2  0.0  0.0  0.56  1.0
  Nb  Nb3  2  0.0  0.0  0.01  1.0
  Nb  Nb4  2  0.0  0.0  0.86  1.0

Y Y Y Nb Nb
Y Y Y Nb Nb 0 4 o o - 0 3 o o o 1 1 + o + 1 1 o + + 1 2 o o o 2 2 + o + 2 2 o + + 3 4 o o - 
Y3Nb2 crystallizes in the monoclinic Cm space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in a distorted single-bond geometry to one Nb(1) and one Nb(2) atom. The Y(1)-Nb(1) bond length is 1.74 Å. The Y(1)-Nb(2) bond length is 0.18 Å. In the second Y site, Y(2) is bonded to one Y(3), four equivalent Y(2), and one Nb(2) atom to form a mixture of edge and corner-sharing YY5Nb octahedra. The corner-sharing octahedra are not tilted. The Y(2)-Y(3) bond length is 3.09 Å. All Y(2)-Y(2) bond lengths are 3.17 Å. The Y(2)-Nb(2) bond length is 3.88 Å. In the third Y site, Y(3) is bonded to one Y(2), four equivalent Y(3), and one Nb(1) atom to form a mixture of edge and corner-sharing YY5Nb octahedra. The corner-sharing octahedra are not tilted. All Y(3)-Y(3) bond lengths are 3.17 Å. The Y(3)-Nb(1) bond length is 3.88 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 Y(3) atom. In the second Nb site, Nb(2) is bonded in a single-bond geometry to one Y(1) and one Y(2) atom.