The crystal structure described by Li2Fe2Si4O11 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), one O(3), and one O(7) atom. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(6), and one O(9) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(7), one O(8), one O(9), and two equivalent O(11) atoms to form FeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and edges with three equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(11), one O(3), one O(7), one O(9), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. There are four inequivalent Si sites. In the first Si site, 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 Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 4-60°. In the second Si site, Si(2) is bonded to one O(10), one O(11), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-64°. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-65°. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(7), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-65°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Li(1), one Li(2), one Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Fe(2), and one Si(1) atom to form distorted OLi2FeSi trigonal pyramids that share  a cornercorner with one O(11)Fe3Si tetrahedra and  an edgeedge with one O(9)LiFe2Si trigonal pyramid. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Li(2), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(2), one Si(3), and one Si(4) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Li(1), one Fe(1), one Fe(2), and one Si(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Fe(1), two equivalent Fe(2), and one Si(3) atom. In the ninth O site, O(9) is bonded to one Li(2), one Fe(1), one Fe(2), and one Si(4) atom to form OLiFe2Si trigonal pyramids that share  a cornercorner with one O(11)Fe3Si tetrahedra,  an edgeedge with one O(11)Fe3Si tetrahedra, and  an edgeedge with one O(3)Li2FeSi trigonal pyramid. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the eleventh O site, O(11) is bonded to one Fe(2), two equivalent Fe(1), and one Si(2) atom to form distorted OFe3Si tetrahedra that share  a cornercorner with one O(3)Li2FeSi trigonal pyramid,  a cornercorner with one O(9)LiFe2Si trigonal pyramid,  an edgeedge with one O(11)Fe3Si tetrahedra, and  an edgeedge with one O(9)LiFe2Si trigonal pyramid. is represented by the CIF file [CIF]
data_Li2Fe2Si4O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.047
_cell_length_b   7.581
_cell_length_c   8.794
_cell_angle_alpha   99.968
_cell_angle_beta   101.127
_cell_angle_gamma   104.425
_symmetry_Int_Tables_number   1
_cell_volume   434.194
_cell_formula_units_Z   2
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  0.389  0.212  0.803  1.0
  Li  Li1  1  0.860  0.250  0.848  1.0
  Li  Li2  1  0.140  0.750  0.152  1.0
  Li  Li3  1  0.611  0.788  0.197  1.0
  Fe  Fe4  1  0.117  0.377  0.612  1.0
  Fe  Fe5  1  0.628  0.382  0.602  1.0
  Fe  Fe6  1  0.372  0.618  0.398  1.0
  Fe  Fe7  1  0.883  0.623  0.388  1.0
  Si  Si8  1  0.761  0.613  0.966  1.0
  Si  Si9  1  0.041  0.774  0.766  1.0
  Si  Si10  1  0.478  0.776  0.773  1.0
  Si  Si11  1  0.232  0.026  0.402  1.0
  Si  Si12  1  0.768  0.974  0.598  1.0
  Si  Si13  1  0.522  0.224  0.227  1.0
  Si  Si14  1  0.959  0.226  0.234  1.0
  Si  Si15  1  0.239  0.387  0.034  1.0
  O  O16  1  0.184  0.374  0.846  1.0
  O  O17  1  0.601  0.740  0.938  1.0
  O  O18  1  0.677  0.407  0.845  1.0
  O  O19  1  0.976  0.736  0.931  1.0
  O  O20  1  0.289  0.846  0.817  1.0
  O  O21  1  0.616  0.958  0.725  1.0
  O  O22  1  0.321  0.189  0.565  1.0
  O  O23  1  0.416  0.590  0.629  1.0
  O  O24  1  0.818  0.193  0.594  1.0
  O  O25  1  0.976  0.949  0.709  1.0
  O  O26  1  0.939  0.586  0.625  1.0
  O  O27  1  0.061  0.414  0.375  1.0
  O  O28  1  0.024  0.051  0.291  1.0
  O  O29  1  0.182  0.807  0.406  1.0
  O  O30  1  0.584  0.410  0.371  1.0
  O  O31  1  0.679  0.811  0.435  1.0
  O  O32  1  0.384  0.042  0.275  1.0
  O  O33  1  0.711  0.154  0.183  1.0
  O  O34  1  0.024  0.264  0.069  1.0
  O  O35  1  0.323  0.593  0.155  1.0
  O  O36  1  0.399  0.260  0.062  1.0
  O  O37  1  0.816  0.626  0.154  1.0
[/CIF]
.
The crystal structure described by Li2Fe2Si4O11 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), one O(3), and one O(7) atom. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(6), and one O(9) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(7), one O(8), one O(9), and two equivalent O(11) atoms to form FeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and edges with three equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(11), one O(3), one O(7), one O(9), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. There are four inequivalent Si sites. In the first Si site, 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 Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 4-60°. In the second Si site, Si(2) is bonded to one O(10), one O(11), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-64°. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-65°. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(7), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-65°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Li(1), one Li(2), one Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Fe(2), and one Si(1) atom to form distorted OLi2FeSi trigonal pyramids that share  a cornercorner with one O(11)Fe3Si tetrahedra and  an edgeedge with one O(9)LiFe2Si trigonal pyramid. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Li(2), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(2), one Si(3), and one Si(4) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Li(1), one Fe(1), one Fe(2), and one Si(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Fe(1), two equivalent Fe(2), and one Si(3) atom. In the ninth O site, O(9) is bonded to one Li(2), one Fe(1), one Fe(2), and one Si(4) atom to form OLiFe2Si trigonal pyramids that share  a cornercorner with one O(11)Fe3Si tetrahedra,  an edgeedge with one O(11)Fe3Si tetrahedra, and  an edgeedge with one O(3)Li2FeSi trigonal pyramid. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the eleventh O site, O(11) is bonded to one Fe(2), two equivalent Fe(1), and one Si(2) atom to form distorted OFe3Si tetrahedra that share  a cornercorner with one O(3)Li2FeSi trigonal pyramid,  a cornercorner with one O(9)LiFe2Si trigonal pyramid,  an edgeedge with one O(11)Fe3Si tetrahedra, and  an edgeedge with one O(9)LiFe2Si trigonal pyramid. is represented by the CIF file [CIF]
data_Li2Fe2Si4O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.047
_cell_length_b   7.581
_cell_length_c   8.794
_cell_angle_alpha   99.968
_cell_angle_beta   101.127
_cell_angle_gamma   104.425
_symmetry_Int_Tables_number   1
_cell_volume   434.194
_cell_formula_units_Z   2
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  0.389  0.212  0.803  1.0
  Li  Li1  1  0.860  0.250  0.848  1.0
  Li  Li2  1  0.140  0.750  0.152  1.0
  Li  Li3  1  0.611  0.788  0.197  1.0
  Fe  Fe4  1  0.117  0.377  0.612  1.0
  Fe  Fe5  1  0.628  0.382  0.602  1.0
  Fe  Fe6  1  0.372  0.618  0.398  1.0
  Fe  Fe7  1  0.883  0.623  0.388  1.0
  Si  Si8  1  0.761  0.613  0.966  1.0
  Si  Si9  1  0.041  0.774  0.766  1.0
  Si  Si10  1  0.478  0.776  0.773  1.0
  Si  Si11  1  0.232  0.026  0.402  1.0
  Si  Si12  1  0.768  0.974  0.598  1.0
  Si  Si13  1  0.522  0.224  0.227  1.0
  Si  Si14  1  0.959  0.226  0.234  1.0
  Si  Si15  1  0.239  0.387  0.034  1.0
  O  O16  1  0.184  0.374  0.846  1.0
  O  O17  1  0.601  0.740  0.938  1.0
  O  O18  1  0.677  0.407  0.845  1.0
  O  O19  1  0.976  0.736  0.931  1.0
  O  O20  1  0.289  0.846  0.817  1.0
  O  O21  1  0.616  0.958  0.725  1.0
  O  O22  1  0.321  0.189  0.565  1.0
  O  O23  1  0.416  0.590  0.629  1.0
  O  O24  1  0.818  0.193  0.594  1.0
  O  O25  1  0.976  0.949  0.709  1.0
  O  O26  1  0.939  0.586  0.625  1.0
  O  O27  1  0.061  0.414  0.375  1.0
  O  O28  1  0.024  0.051  0.291  1.0
  O  O29  1  0.182  0.807  0.406  1.0
  O  O30  1  0.584  0.410  0.371  1.0
  O  O31  1  0.679  0.811  0.435  1.0
  O  O32  1  0.384  0.042  0.275  1.0
  O  O33  1  0.711  0.154  0.183  1.0
  O  O34  1  0.024  0.264  0.069  1.0
  O  O35  1  0.323  0.593  0.155  1.0
  O  O36  1  0.399  0.260  0.062  1.0
  O  O37  1  0.816  0.626  0.154  1.0
[/CIF]
.