The material described by Li2Fe(Si2O5)3 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(3), one O(8), and two equivalent O(4) atoms to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 41°. Fe(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and edges with two equivalent Li(1)O4 trigonal pyramids. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 42°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid, and  an edgeedge with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 61°. In the third Si site, Si(3) is bonded to one O(1), 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,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 45°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Si(3) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded to two equivalent Li(1), one Fe(1), and one Si(2) atom to form a mixture of distorted edge and corner-sharing OLi2FeSi trigonal pyramids. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_Li2Fe(Si2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.861
_cell_length_b   7.303
_cell_length_c   7.490
_cell_angle_alpha   96.963
_cell_angle_beta   112.676
_cell_angle_gamma   113.181
_symmetry_Int_Tables_number   1
_cell_volume   301.403
_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  1.000  1.000  1.000  1.0
  Li  Li1  1  0.713  0.173  0.143  1.0
  Li  Li2  1  0.287  0.827  0.857  1.0
  O  O3  1  0.500  0.500  0.500  1.0
  O  O4  1  0.821  0.048  0.767  1.0
  O  O5  1  0.179  0.952  0.233  1.0
  O  O6  1  0.305  0.982  0.628  1.0
  O  O7  1  0.695  0.018  0.372  1.0
  O  O8  1  0.351  0.133  0.982  1.0
  O  O9  1  0.649  0.867  0.018  1.0
  O  O10  1  0.827  0.375  0.616  1.0
  O  O11  1  0.173  0.625  0.384  1.0
  O  O12  1  0.615  0.394  0.842  1.0
  O  O13  1  0.385  0.606  0.158  1.0
  O  O14  1  0.151  0.263  0.659  1.0
  O  O15  1  0.849  0.737  0.341  1.0
  O  O16  1  0.053  0.257  0.167  1.0
  O  O17  1  0.947  0.743  0.832  1.0
  Si  Si18  1  0.872  0.173  0.611  1.0
  Si  Si19  1  0.128  0.827  0.389  1.0
  Si  Si20  1  0.354  0.198  0.784  1.0
  Si  Si21  1  0.646  0.802  0.216  1.0
  Si  Si22  1  0.718  0.509  0.698  1.0
  Si  Si23  1  0.282  0.491  0.302  1.0
[/CIF]
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The material described by Li2Fe(Si2O5)3 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(3), one O(8), and two equivalent O(4) atoms to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 41°. Fe(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and edges with two equivalent Li(1)O4 trigonal pyramids. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 42°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid, and  an edgeedge with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 61°. In the third Si site, Si(3) is bonded to one O(1), 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,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 45°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Si(3) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded to two equivalent Li(1), one Fe(1), and one Si(2) atom to form a mixture of distorted edge and corner-sharing OLi2FeSi trigonal pyramids. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_Li2Fe(Si2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.861
_cell_length_b   7.303
_cell_length_c   7.490
_cell_angle_alpha   96.963
_cell_angle_beta   112.676
_cell_angle_gamma   113.181
_symmetry_Int_Tables_number   1
_cell_volume   301.403
_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  1.000  1.000  1.000  1.0
  Li  Li1  1  0.713  0.173  0.143  1.0
  Li  Li2  1  0.287  0.827  0.857  1.0
  O  O3  1  0.500  0.500  0.500  1.0
  O  O4  1  0.821  0.048  0.767  1.0
  O  O5  1  0.179  0.952  0.233  1.0
  O  O6  1  0.305  0.982  0.628  1.0
  O  O7  1  0.695  0.018  0.372  1.0
  O  O8  1  0.351  0.133  0.982  1.0
  O  O9  1  0.649  0.867  0.018  1.0
  O  O10  1  0.827  0.375  0.616  1.0
  O  O11  1  0.173  0.625  0.384  1.0
  O  O12  1  0.615  0.394  0.842  1.0
  O  O13  1  0.385  0.606  0.158  1.0
  O  O14  1  0.151  0.263  0.659  1.0
  O  O15  1  0.849  0.737  0.341  1.0
  O  O16  1  0.053  0.257  0.167  1.0
  O  O17  1  0.947  0.743  0.832  1.0
  Si  Si18  1  0.872  0.173  0.611  1.0
  Si  Si19  1  0.128  0.827  0.389  1.0
  Si  Si20  1  0.354  0.198  0.784  1.0
  Si  Si21  1  0.646  0.802  0.216  1.0
  Si  Si22  1  0.718  0.509  0.698  1.0
  Si  Si23  1  0.282  0.491  0.302  1.0
[/CIF]
.