data_Li4Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.84
_cell_length_b   4.84
_cell_length_c   4.84
_cell_angle_alpha   123.12
_cell_angle_beta   123.12
_cell_angle_gamma   84.67
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Li4Si
_chemical_formula_sum   'Li4 Si1'
_cell_volume   75.95
_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
  Li  Li0  1  0.0  0.3  0.79  1.0
  Li  Li1  1  0.3  0.0  0.79  1.0
  Li  Li2  1  0.0  0.0  0.49  1.0
  Li  Li3  1  0.0  0.0  0.67  1.0
  Si  Si4  1  0.0  0.0  0.0  1.0

data_Li4Si
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.52
_cell_length_b   6.52
_cell_length_c   4.84
_cell_angle_alpha   90.0
_cell_angle_beta   132.33
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Li4Si
_chemical_formula_sum   'Li8 Si2'
_cell_volume   151.91
_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
  Li  Li0  4  0.35  0.35  0.48  1.0
  Li  Li1  2  0.0  0.0  0.49  1.0
  Li  Li2  2  0.0  0.0  0.67  1.0
  Si  Si3  2  0.0  0.0  0.0  1.0

Li Li Li Li Si
Li Li Li Li Si 0 2 o o o 0 3 o o o 1 2 o o o 1 3 o o o 2 3 o o o 3 4 o o + 
Li4Si crystallizes in the monoclinic Cm space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), and two equivalent Si(1) atoms. The Li(1)-Li(2) bond length is 1.39 Å. The Li(1)-Li(3) bond length is 1.25 Å. There is one shorter (2.20 Å) and one longer (2.94 Å) Li(1)-Si(1) bond length. In the second Li site, Li(2) is bonded in a distorted linear geometry to one Li(3), two equivalent Li(1), and one Si(1) atom. The Li(2)-Li(3) bond length is 0.86 Å. The Li(2)-Si(1) bond length is 2.36 Å. In the third Li site, Li(3) is bonded in a distorted see-saw-like geometry to one Li(2), two equivalent Li(1), and one Si(1) atom. The Li(3)-Si(1) bond length is 1.62 Å. Si(1) is bonded in a 6-coordinate geometry to one Li(2), one Li(3), and four equivalent Li(1) atoms.