data_AlFe2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.81
_cell_length_b   2.81
_cell_length_c   5.64
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   AlFe2Si
_chemical_formula_sum   'Al1 Fe2 Si1'
_cell_volume   44.43
_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
  Al  Al0  1  0.0  0.0  0.0  1.0
  Fe  Fe1  1  0.4  0.4  0.5  1.0
  Fe  Fe2  1  0.4  0.4  0.14  1.0
  Si  Si3  1  0.0  0.0  0.82  1.0

data_AlFe2Si
_symmetry_space_group_name_H-M   Cm
_cell_length_a   3.97
_cell_length_b   3.97
_cell_length_c   5.64
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   AlFe2Si
_chemical_formula_sum   'Al2 Fe4 Si2'
_cell_volume   88.86
_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
  Al  Al0  2  0.0  0.0  0.0  1.0
  Fe  Fe1  2  0.4  0.0  0.14  1.0
  Fe  Fe2  2  0.4  0.0  0.5  1.0
  Si  Si3  2  0.0  0.0  0.82  1.0

Al Fe Fe Si
Fe2AlSi crystallizes in the monoclinic Cm space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 9-coordinate geometry to one Fe(2), four equivalent Fe(1), and four equivalent Si(1) atoms. The Fe(1)-Fe(2) bond length is 2.02 Å. All Fe(1)-Fe(1) bond lengths are 2.81 Å. There are a spread of Fe(1)-Si(1) bond distances ranging from 2.42-2.98 Å. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one Fe(1) and four equivalent Al(1) atoms. There are a spread of Fe(2)-Al(1) bond distances ranging from 1.79-2.50 Å. Al(1) is bonded in a distorted single-bond geometry to four equivalent Fe(2) and one Si(1) atom. The Al(1)-Si(1) bond length is 1.02 Å. Si(1) is bonded in a single-bond geometry to four equivalent Fe(1) and one Al(1) atom.