data_Na2NbFe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.29
_cell_length_b   3.29
_cell_length_c   7.02
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2NbFe
_chemical_formula_sum   'Na2 Nb1 Fe1'
_cell_volume   75.71
_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
  Na  Na1  1  0.64  0.64  0.49  1.0
  Na  Na2  1  0.64  0.64  0.53  1.0
  Nb  Nb3  1  0.0  0.0  0.51  1.0
  Fe  Fe0  1  0.0  0.0  0.0  1.0

data_Na2NbFe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.65
_cell_length_b   4.65
_cell_length_c   7.02
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na2NbFe
_chemical_formula_sum   'Na4 Nb2 Fe2'
_cell_volume   151.42
_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
  Na  Na0  2  0.14  0.5  0.49  1.0
  Na  Na1  2  0.14  0.5  0.53  1.0
  Nb  Nb2  2  0.0  0.0  0.51  1.0
  Fe  Fe3  2  0.0  0.0  0.0  1.0

Na Na Nb Fe
Na Na Nb Fe 0 1 o o o 0 2 + + o 0 3 + + + 0 3 + + o 1 2 + + o 1 3 + + + 1 3 + + o 1 3 + o + 1 3 o + + 2 3 o o + 2 3 o o o 3 3 + o o 3 3 o + o 
Na2NbFe crystallizes in the monoclinic Cm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a single-bond geometry to one Na(2), one Nb(1), and one Fe(1) atom. The Na(1)-Na(2) bond length is 0.27 Å. The Na(1)-Nb(1) bond length is 1.67 Å. The Na(1)-Fe(1) bond length is 3.81 Å. In the second Na site, Na(2) is bonded in a single-bond geometry to one Na(1), one Nb(1), and one Fe(1) atom. The Na(2)-Nb(1) bond length is 1.67 Å. The Na(2)-Fe(1) bond length is 3.71 Å. Nb(1) is bonded in a 2-coordinate geometry to one Na(1), one Na(2), and two equivalent Fe(1) atoms. There is one shorter (3.45 Å) and one longer (3.56 Å) Nb(1)-Fe(1) bond length. Fe(1) is bonded to one Na(1), one Na(2), two equivalent Nb(1), and four equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing FeNa2Nb2Fe4 hexagonal bipyramids. All Fe(1)-Fe(1) bond lengths are 3.29 Å.