The material described by Li4FeSi2O7 is Stannite-like structured and crystallizes in the monoclinic C2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form LiO4 tetrahedra that share  a cornercorner with one Fe(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and corners with five equivalent Si(1)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and corners with four equivalent Si(1)O4 tetrahedra. Fe(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted FeO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and corners with six equivalent Li(2)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and corners with five equivalent Li(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1) and two equivalent Si(1) atoms to form OLi2Si2 tetrahedra that share corners with two equivalent O(3)Li2FeSi tetrahedra, corners with four equivalent O(2)Li2FeSi tetrahedra, and corners with six equivalent O(4)Li3Si tetrahedra. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Fe(1), and one Si(1) atom to form OLi2FeSi tetrahedra that share  a cornercorner with one O(2)Li2FeSi tetrahedra, corners with two equivalent O(1)Li2Si2 tetrahedra, corners with four equivalent O(4)Li3Si tetrahedra, and corners with five equivalent O(3)Li2FeSi tetrahedra. In the third O site, O(3) is bonded to two equivalent Li(2), one Fe(1), and one Si(1) atom to form OLi2FeSi tetrahedra that share  a cornercorner with one O(1)Li2Si2 tetrahedra, corners with three equivalent O(3)Li2FeSi tetrahedra, corners with three equivalent O(4)Li3Si tetrahedra, and corners with five equivalent O(2)Li2FeSi tetrahedra. In the fourth O site, O(4) is bonded to one Li(2), two equivalent Li(1), and one Si(1) atom to form OLi3Si tetrahedra that share corners with two equivalent O(4)Li3Si tetrahedra, corners with three equivalent O(3)Li2FeSi tetrahedra, corners with three equivalent O(1)Li2Si2 tetrahedra, and corners with four equivalent O(2)Li2FeSi tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li4FeSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.557
_cell_length_b   5.322
_cell_length_c   6.858
_cell_angle_alpha   99.524
_cell_angle_beta   90.009
_cell_angle_gamma   115.338
_symmetry_Int_Tables_number   1
_cell_volume   147.760
_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
  Fe  Fe0  1  0.999  1.000  1.000  1.0
  Li  Li1  1  0.131  0.298  0.437  1.0
  Li  Li2  1  0.833  0.702  0.563  1.0
  Li  Li3  1  0.707  0.426  0.147  1.0
  Li  Li4  1  0.281  0.574  0.853  1.0
  O  O5  1  0.318  1.000  0.500  1.0
  O  O6  1  0.765  0.104  0.229  1.0
  O  O7  1  0.660  0.896  0.771  1.0
  O  O8  1  0.405  0.265  0.887  1.0
  O  O9  1  0.141  0.736  0.114  1.0
  O  O10  1  0.911  0.409  0.657  1.0
  O  O11  1  0.502  0.591  0.343  1.0
  Si  Si12  1  0.585  0.151  0.709  1.0
  Si  Si13  1  0.435  0.849  0.291  1.0
[/CIF]
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The material described by Li4FeSi2O7 is Stannite-like structured and crystallizes in the monoclinic C2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form LiO4 tetrahedra that share  a cornercorner with one Fe(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and corners with five equivalent Si(1)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and corners with four equivalent Si(1)O4 tetrahedra. Fe(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted FeO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and corners with six equivalent Li(2)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and corners with five equivalent Li(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1) and two equivalent Si(1) atoms to form OLi2Si2 tetrahedra that share corners with two equivalent O(3)Li2FeSi tetrahedra, corners with four equivalent O(2)Li2FeSi tetrahedra, and corners with six equivalent O(4)Li3Si tetrahedra. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Fe(1), and one Si(1) atom to form OLi2FeSi tetrahedra that share  a cornercorner with one O(2)Li2FeSi tetrahedra, corners with two equivalent O(1)Li2Si2 tetrahedra, corners with four equivalent O(4)Li3Si tetrahedra, and corners with five equivalent O(3)Li2FeSi tetrahedra. In the third O site, O(3) is bonded to two equivalent Li(2), one Fe(1), and one Si(1) atom to form OLi2FeSi tetrahedra that share  a cornercorner with one O(1)Li2Si2 tetrahedra, corners with three equivalent O(3)Li2FeSi tetrahedra, corners with three equivalent O(4)Li3Si tetrahedra, and corners with five equivalent O(2)Li2FeSi tetrahedra. In the fourth O site, O(4) is bonded to one Li(2), two equivalent Li(1), and one Si(1) atom to form OLi3Si tetrahedra that share corners with two equivalent O(4)Li3Si tetrahedra, corners with three equivalent O(3)Li2FeSi tetrahedra, corners with three equivalent O(1)Li2Si2 tetrahedra, and corners with four equivalent O(2)Li2FeSi tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li4FeSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.557
_cell_length_b   5.322
_cell_length_c   6.858
_cell_angle_alpha   99.524
_cell_angle_beta   90.009
_cell_angle_gamma   115.338
_symmetry_Int_Tables_number   1
_cell_volume   147.760
_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
  Fe  Fe0  1  0.999  1.000  1.000  1.0
  Li  Li1  1  0.131  0.298  0.437  1.0
  Li  Li2  1  0.833  0.702  0.563  1.0
  Li  Li3  1  0.707  0.426  0.147  1.0
  Li  Li4  1  0.281  0.574  0.853  1.0
  O  O5  1  0.318  1.000  0.500  1.0
  O  O6  1  0.765  0.104  0.229  1.0
  O  O7  1  0.660  0.896  0.771  1.0
  O  O8  1  0.405  0.265  0.887  1.0
  O  O9  1  0.141  0.736  0.114  1.0
  O  O10  1  0.911  0.409  0.657  1.0
  O  O11  1  0.502  0.591  0.343  1.0
  Si  Si12  1  0.585  0.151  0.709  1.0
  Si  Si13  1  0.435  0.849  0.291  1.0
[/CIF]
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