data_NaFe2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.71
_cell_length_b   2.81
_cell_length_c   7.72
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaFe2Si
_chemical_formula_sum   'Na1 Fe2 Si1'
_cell_volume   58.7
_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  Na2  1  0.0  0.0  0.0  1.0
  Fe  Fe0  1  0.35  0.4  0.23  1.0
  Fe  Fe1  1  0.35  0.4  0.49  1.0
  Si  Si3  1  0.0  0.0  0.86  1.0

data_NaFe2Si
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.71
_cell_length_b   2.81
_cell_length_c   7.72
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaFe2Si
_chemical_formula_sum   'Na1 Fe2 Si1'
_cell_volume   58.7
_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  Na0  1  0.0  0.0  0.0  1.0
  Fe  Fe1  1  0.35  0.4  0.23  1.0
  Fe  Fe2  1  0.35  0.4  0.49  1.0
  Si  Si3  1  0.0  0.0  0.86  1.0

Na Fe Fe Si
Na Fe Fe Si 0 3 o o - 0 1 o o o 0 1 o - o 1 1 + o o 1 2 o o o 
NaFe2Si crystallizes in the triclinic P1 space group. Na(1) is bonded in a distorted single-bond geometry to four equivalent Fe(1) and one Si(1) atom. There are a spread of Na(1)-Fe(1) bond distances ranging from 2.31-3.00 Å. The Na(1)-Si(1) bond length is 1.07 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 9-coordinate geometry to four equivalent Na(1), one Fe(2), and four equivalent Fe(1) atoms. The Fe(1)-Fe(2) bond length is 2.04 Å. There are two shorter (2.71 Å) and two longer (2.81 Å) Fe(1)-Fe(1) bond lengths. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one Fe(1), four equivalent Fe(2), and one Si(1) atom. There are two shorter (2.71 Å) and two longer (2.81 Å) Fe(2)-Fe(2) bond lengths. The Fe(2)-Si(1) bond length is 3.21 Å. Si(1) is bonded in a single-bond geometry to one Na(1) and one Fe(2) atom.