The compound described by Nb3FeSe6 is Corundum-derived structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent Fe(1)Se6 octahedra and edges with six equivalent Nb(4)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 46-47°. In the second Nb site, Nb(2) is bonded to two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent Fe(1)Se6 octahedra and edges with six equivalent Nb(3)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 46-47°. In the third Nb site, Nb(3) is bonded to two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent Fe(1)Se6 octahedra, edges with three equivalent Nb(2)Se6 pentagonal pyramids, edges with three equivalent Nb(3)Se6 pentagonal pyramids, and  a faceface with one Fe(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. In the fourth Nb site, Nb(4) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent Fe(1)Se6 octahedra, edges with three equivalent Nb(1)Se6 pentagonal pyramids, edges with three equivalent Nb(4)Se6 pentagonal pyramids, and  a faceface with one Fe(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. Fe(1) is bonded to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom to form FeSe6 octahedra that share corners with three equivalent Nb(1)Se6 pentagonal pyramids, corners with three equivalent Nb(2)Se6 pentagonal pyramids, corners with three equivalent Nb(3)Se6 pentagonal pyramids, corners with three equivalent Nb(4)Se6 pentagonal pyramids,  a faceface with one Nb(3)Se6 pentagonal pyramid, and  a faceface with one Nb(4)Se6 pentagonal pyramid. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Nb(1), two equivalent Nb(4), and one Fe(1) atom. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Nb(1), two equivalent Nb(4), and one Fe(1) atom. In the third Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Nb(1), two equivalent Nb(4), and one Fe(1) atom. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(3), and one Fe(1) atom. In the fifth Se site, Se(5) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(3), and one Fe(1) atom. In the sixth Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(3), and one Fe(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Nb3FeSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.074
_cell_length_b   6.073
_cell_length_c   12.865
_cell_angle_alpha   89.958
_cell_angle_beta   90.039
_cell_angle_gamma   119.970
_symmetry_Int_Tables_number   1
_cell_volume   411.111
_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  0.999  0.999  0.500  1.0
  Nb  Nb1  1  1.000  1.000  0.000  1.0
  Nb  Nb2  1  0.333  0.666  0.000  1.0
  Nb  Nb3  1  0.666  0.333  0.000  1.0
  Nb  Nb4  1  0.668  0.333  0.500  1.0
  Nb  Nb5  1  0.333  0.668  0.500  1.0
  Fe  Fe6  1  0.334  0.667  0.250  1.0
  Fe  Fe7  1  0.667  0.334  0.750  1.0
  Se  Se8  1  0.333  0.331  0.371  1.0
  Se  Se9  1  0.671  0.004  0.370  1.0
  Se  Se10  1  0.996  0.667  0.370  1.0
  Se  Se11  1  0.331  0.333  0.629  1.0
  Se  Se12  1  0.004  0.671  0.629  1.0
  Se  Se13  1  0.667  0.996  0.629  1.0
  Se  Se14  1  0.667  0.671  0.871  1.0
  Se  Se15  1  0.329  0.996  0.871  1.0
  Se  Se16  1  0.002  0.333  0.871  1.0
  Se  Se17  1  0.671  0.667  0.130  1.0
  Se  Se18  1  0.996  0.329  0.130  1.0
  Se  Se19  1  0.333  0.002  0.129  1.0
[/CIF]
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The compound described by Nb3FeSe6 is Corundum-derived structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent Fe(1)Se6 octahedra and edges with six equivalent Nb(4)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 46-47°. In the second Nb site, Nb(2) is bonded to two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent Fe(1)Se6 octahedra and edges with six equivalent Nb(3)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 46-47°. In the third Nb site, Nb(3) is bonded to two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent Fe(1)Se6 octahedra, edges with three equivalent Nb(2)Se6 pentagonal pyramids, edges with three equivalent Nb(3)Se6 pentagonal pyramids, and  a faceface with one Fe(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. In the fourth Nb site, Nb(4) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent Fe(1)Se6 octahedra, edges with three equivalent Nb(1)Se6 pentagonal pyramids, edges with three equivalent Nb(4)Se6 pentagonal pyramids, and  a faceface with one Fe(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. Fe(1) is bonded to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom to form FeSe6 octahedra that share corners with three equivalent Nb(1)Se6 pentagonal pyramids, corners with three equivalent Nb(2)Se6 pentagonal pyramids, corners with three equivalent Nb(3)Se6 pentagonal pyramids, corners with three equivalent Nb(4)Se6 pentagonal pyramids,  a faceface with one Nb(3)Se6 pentagonal pyramid, and  a faceface with one Nb(4)Se6 pentagonal pyramid. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Nb(1), two equivalent Nb(4), and one Fe(1) atom. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Nb(1), two equivalent Nb(4), and one Fe(1) atom. In the third Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Nb(1), two equivalent Nb(4), and one Fe(1) atom. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(3), and one Fe(1) atom. In the fifth Se site, Se(5) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(3), and one Fe(1) atom. In the sixth Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(3), and one Fe(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Nb3FeSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.074
_cell_length_b   6.073
_cell_length_c   12.865
_cell_angle_alpha   89.958
_cell_angle_beta   90.039
_cell_angle_gamma   119.970
_symmetry_Int_Tables_number   1
_cell_volume   411.111
_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  0.999  0.999  0.500  1.0
  Nb  Nb1  1  1.000  1.000  0.000  1.0
  Nb  Nb2  1  0.333  0.666  0.000  1.0
  Nb  Nb3  1  0.666  0.333  0.000  1.0
  Nb  Nb4  1  0.668  0.333  0.500  1.0
  Nb  Nb5  1  0.333  0.668  0.500  1.0
  Fe  Fe6  1  0.334  0.667  0.250  1.0
  Fe  Fe7  1  0.667  0.334  0.750  1.0
  Se  Se8  1  0.333  0.331  0.371  1.0
  Se  Se9  1  0.671  0.004  0.370  1.0
  Se  Se10  1  0.996  0.667  0.370  1.0
  Se  Se11  1  0.331  0.333  0.629  1.0
  Se  Se12  1  0.004  0.671  0.629  1.0
  Se  Se13  1  0.667  0.996  0.629  1.0
  Se  Se14  1  0.667  0.671  0.871  1.0
  Se  Se15  1  0.329  0.996  0.871  1.0
  Se  Se16  1  0.002  0.333  0.871  1.0
  Se  Se17  1  0.671  0.667  0.130  1.0
  Se  Se18  1  0.996  0.329  0.130  1.0
  Se  Se19  1  0.333  0.002  0.129  1.0
[/CIF]
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