data_NbFe2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.69
_cell_length_b   3.69
_cell_length_c   4.25
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NbFe2Se
_chemical_formula_sum   'Nb1 Fe2 Se1'
_cell_volume   57.85
_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
  Nb  Nb2  1  0.84  0.84  0.0  1.0
  Fe  Fe0  1  0.0  0.84  0.12  1.0
  Fe  Fe1  1  0.84  0.0  0.12  1.0
  Se  Se3  1  0.0  0.0  0.0  1.0

data_NbFe2Se
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.22
_cell_length_b   5.22
_cell_length_c   4.25
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   NbFe2Se
_chemical_formula_sum   'Nb2 Fe4 Se2'
_cell_volume   115.69
_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
  Nb  Nb0  2  0.34  0.5  0.0  1.0
  Fe  Fe1  4  0.42  0.42  0.12  1.0
  Se  Se2  2  0.0  0.0  0.0  1.0

Nb Fe Fe Se
Nb Fe Fe Se 0 3 + + o 0 2 o + o 0 1 + o o 1 2 - + o 1 3 o + o 2 3 + o o 
NbFe2Se is alpha Po structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two NbFe2Se clusters. Nb(1) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one Se(1) atom. Both Nb(1)-Fe(1) bond lengths are 0.78 Å. The Nb(1)-Se(1) bond length is 0.81 Å. Fe(1) is bonded in a 2-coordinate geometry to one Nb(1) and one Se(1) atom. The Fe(1)-Se(1) bond length is 0.78 Å. Se(1) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Fe(1) atoms.