The material structure described by Nb2Se3 crystallizes in the monoclinic Pm space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Se(2), one Se(3), one Se(4), and two equivalent Se(6) atoms to form distorted NbSe5 trigonal bipyramids that share corners with four equivalent Nb(4)Se6 octahedra, corners with two equivalent Nb(2)Se6 pentagonal pyramids, corners with two equivalent Nb(1)Se5 trigonal bipyramids, and edges with two equivalent Nb(2)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 40-43°. In the second Nb site, Nb(2) is bonded to one Se(5), one Se(6), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NbSe6 pentagonal pyramids that share corners with two equivalent Nb(4)Se6 octahedra, corners with two equivalent Nb(1)Se5 trigonal bipyramids, edges with two equivalent Nb(2)Se6 pentagonal pyramids, edges with two equivalent Nb(1)Se5 trigonal bipyramids, and  a faceface with one Nb(4)Se6 octahedra. The corner-sharing octahedral tilt angles are 46°. In the third Nb site, Nb(3) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(1), two equivalent Se(5), and two equivalent Se(6) atoms. In the fourth Nb site, Nb(4) is bonded to one Se(1), one Se(5), two equivalent Se(2), and two equivalent Se(4) atoms to form NbSe6 octahedra that share corners with two equivalent Nb(2)Se6 pentagonal pyramids, corners with four equivalent Nb(1)Se5 trigonal bipyramids, edges with two equivalent Nb(4)Se6 octahedra, and  a faceface with one Nb(2)Se6 pentagonal pyramid. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Nb(4) and two equivalent Nb(3) atoms. In the second Se site, Se(2) is bonded to one Nb(1), one Nb(3), two equivalent Nb(2), and two equivalent Nb(4) atoms to form distorted SeNb6 pentagonal pyramids that share corners with two equivalent Se(6)Nb5 trigonal bipyramids, edges with two equivalent Se(2)Nb6 pentagonal pyramids, and edges with two equivalent Se(6)Nb5 trigonal bipyramids. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Nb(1) and two equivalent Nb(2) atoms. In the fourth Se site, Se(4) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Nb(4) atoms. In the fifth Se site, Se(5) is bonded in a distorted rectangular see-saw-like geometry to one Nb(2), one Nb(4), and two equivalent Nb(3) atoms. In the sixth Se site, Se(6) is bonded to one Nb(2), two equivalent Nb(1), and two equivalent Nb(3) atoms to form distorted SeNb5 trigonal bipyramids that share corners with two equivalent Se(2)Nb6 pentagonal pyramids, edges with two equivalent Se(2)Nb6 pentagonal pyramids, and edges with two equivalent Se(6)Nb5 trigonal bipyramids. is represented by the CIF file [CIF]
data_Nb2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.349
_cell_length_b   7.906
_cell_length_c   10.331
_cell_angle_alpha   63.050
_cell_angle_beta   90.000
_cell_angle_gamma   115.065
_symmetry_Int_Tables_number   1
_cell_volume   214.554
_cell_formula_units_Z   2
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
  Nb  Nb0  1  0.012  0.012  0.586  1.0
  Nb  Nb1  1  0.027  0.527  0.747  1.0
  Nb  Nb2  1  0.994  0.994  0.945  1.0
  Nb  Nb3  1  0.004  0.504  0.094  1.0
  Se  Se4  1  0.251  0.751  0.193  1.0
  Se  Se5  1  0.681  0.681  0.862  1.0
  Se  Se6  1  0.699  0.699  0.527  1.0
  Se  Se7  1  0.284  0.284  0.314  1.0
  Se  Se8  1  0.692  0.192  0.029  1.0
  Se  Se9  1  0.690  0.190  0.704  1.0
[/CIF]
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The material structure described by Nb2Se3 crystallizes in the monoclinic Pm space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Se(2), one Se(3), one Se(4), and two equivalent Se(6) atoms to form distorted NbSe5 trigonal bipyramids that share corners with four equivalent Nb(4)Se6 octahedra, corners with two equivalent Nb(2)Se6 pentagonal pyramids, corners with two equivalent Nb(1)Se5 trigonal bipyramids, and edges with two equivalent Nb(2)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 40-43°. In the second Nb site, Nb(2) is bonded to one Se(5), one Se(6), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NbSe6 pentagonal pyramids that share corners with two equivalent Nb(4)Se6 octahedra, corners with two equivalent Nb(1)Se5 trigonal bipyramids, edges with two equivalent Nb(2)Se6 pentagonal pyramids, edges with two equivalent Nb(1)Se5 trigonal bipyramids, and  a faceface with one Nb(4)Se6 octahedra. The corner-sharing octahedral tilt angles are 46°. In the third Nb site, Nb(3) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(1), two equivalent Se(5), and two equivalent Se(6) atoms. In the fourth Nb site, Nb(4) is bonded to one Se(1), one Se(5), two equivalent Se(2), and two equivalent Se(4) atoms to form NbSe6 octahedra that share corners with two equivalent Nb(2)Se6 pentagonal pyramids, corners with four equivalent Nb(1)Se5 trigonal bipyramids, edges with two equivalent Nb(4)Se6 octahedra, and  a faceface with one Nb(2)Se6 pentagonal pyramid. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Nb(4) and two equivalent Nb(3) atoms. In the second Se site, Se(2) is bonded to one Nb(1), one Nb(3), two equivalent Nb(2), and two equivalent Nb(4) atoms to form distorted SeNb6 pentagonal pyramids that share corners with two equivalent Se(6)Nb5 trigonal bipyramids, edges with two equivalent Se(2)Nb6 pentagonal pyramids, and edges with two equivalent Se(6)Nb5 trigonal bipyramids. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Nb(1) and two equivalent Nb(2) atoms. In the fourth Se site, Se(4) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Nb(4) atoms. In the fifth Se site, Se(5) is bonded in a distorted rectangular see-saw-like geometry to one Nb(2), one Nb(4), and two equivalent Nb(3) atoms. In the sixth Se site, Se(6) is bonded to one Nb(2), two equivalent Nb(1), and two equivalent Nb(3) atoms to form distorted SeNb5 trigonal bipyramids that share corners with two equivalent Se(2)Nb6 pentagonal pyramids, edges with two equivalent Se(2)Nb6 pentagonal pyramids, and edges with two equivalent Se(6)Nb5 trigonal bipyramids. is represented by the CIF file [CIF]
data_Nb2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.349
_cell_length_b   7.906
_cell_length_c   10.331
_cell_angle_alpha   63.050
_cell_angle_beta   90.000
_cell_angle_gamma   115.065
_symmetry_Int_Tables_number   1
_cell_volume   214.554
_cell_formula_units_Z   2
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
  Nb  Nb0  1  0.012  0.012  0.586  1.0
  Nb  Nb1  1  0.027  0.527  0.747  1.0
  Nb  Nb2  1  0.994  0.994  0.945  1.0
  Nb  Nb3  1  0.004  0.504  0.094  1.0
  Se  Se4  1  0.251  0.751  0.193  1.0
  Se  Se5  1  0.681  0.681  0.862  1.0
  Se  Se6  1  0.699  0.699  0.527  1.0
  Se  Se7  1  0.284  0.284  0.314  1.0
  Se  Se8  1  0.692  0.192  0.029  1.0
  Se  Se9  1  0.690  0.190  0.704  1.0
[/CIF]
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