The structure described by Li2Fe5(Si2O7)2 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Fe(3)O5 trigonal bipyramids,  an edgeedge with one Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(4), and two equivalent O(2) atoms. In the second Fe site, Fe(2) is bonded in a square co-planar geometry to two equivalent O(5) and two equivalent O(7) atoms. In the third Fe site, Fe(3) is bonded to one O(4), one O(5), one O(7), and two equivalent O(6) atoms to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and corners with two equivalent Fe(3)O5 trigonal bipyramids. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, corners with three equivalent Fe(3)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Fe(1), and one Si(2) atom to form OLi2FeSi trigonal pyramids that share  a cornercorner with one O(4)LiFe2Si tetrahedra,  a cornercorner with one O(5)LiFe2Si trigonal pyramid,  an edgeedge with one O(4)LiFe2Si tetrahedra,  an edgeedge with one O(1)Li2FeSi trigonal pyramid, and  an edgeedge with one O(5)LiFe2Si trigonal pyramid. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded to one Li(1), one Fe(1), one Fe(3), and one Si(1) atom to form distorted OLiFe2Si tetrahedra that share  a cornercorner with one O(1)Li2FeSi trigonal pyramid, corners with two equivalent O(5)LiFe2Si trigonal pyramids, and  an edgeedge with one O(1)Li2FeSi trigonal pyramid. In the fifth O site, O(5) is bonded to one Li(1), one Fe(2), one Fe(3), and one Si(2) atom to form distorted OLiFe2Si trigonal pyramids that share corners with two equivalent O(4)LiFe2Si tetrahedra,  a cornercorner with one O(1)Li2FeSi trigonal pyramid,  a cornercorner with one O(5)LiFe2Si trigonal pyramid, and  an edgeedge with one O(1)Li2FeSi trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Fe(3) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Si(1) atom. is represented by the CIF card [CIF]
data_Li2Fe5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.544
_cell_length_b   7.567
_cell_length_c   8.112
_cell_angle_alpha   114.829
_cell_angle_beta   91.546
_cell_angle_gamma   104.392
_symmetry_Int_Tables_number   1
_cell_volume   295.820
_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  0.231  0.101  0.455  1.0
  Li  Li1  1  0.769  0.899  0.545  1.0
  Fe  Fe2  1  0.074  0.388  0.810  1.0
  Fe  Fe3  1  0.926  0.612  0.190  1.0
  Fe  Fe4  1  0.000  1.000  0.000  1.0
  Fe  Fe5  1  0.636  0.583  0.705  1.0
  Fe  Fe6  1  0.364  0.417  0.295  1.0
  Si  Si7  1  0.500  0.223  0.863  1.0
  Si  Si8  1  0.500  0.777  0.137  1.0
  Si  Si9  1  0.789  0.210  0.392  1.0
  Si  Si10  1  0.211  0.790  0.608  1.0
  O  O11  1  0.884  0.180  0.568  1.0
  O  O12  1  0.116  0.820  0.432  1.0
  O  O13  1  0.792  0.339  0.961  1.0
  O  O14  1  0.208  0.661  0.039  1.0
  O  O15  1  0.528  0.019  0.277  1.0
  O  O16  1  0.472  0.981  0.723  1.0
  O  O17  1  0.408  0.326  0.736  1.0
  O  O18  1  0.592  0.674  0.263  1.0
  O  O19  1  0.022  0.186  0.268  1.0
  O  O20  1  0.978  0.814  0.732  1.0
  O  O21  1  0.696  0.412  0.439  1.0
  O  O22  1  0.304  0.588  0.561  1.0
  O  O23  1  0.313  0.227  0.017  1.0
  O  O24  1  0.687  0.773  0.983  1.0
[/CIF]
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The structure described by Li2Fe5(Si2O7)2 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Fe(3)O5 trigonal bipyramids,  an edgeedge with one Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(4), and two equivalent O(2) atoms. In the second Fe site, Fe(2) is bonded in a square co-planar geometry to two equivalent O(5) and two equivalent O(7) atoms. In the third Fe site, Fe(3) is bonded to one O(4), one O(5), one O(7), and two equivalent O(6) atoms to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and corners with two equivalent Fe(3)O5 trigonal bipyramids. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, corners with three equivalent Fe(3)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Fe(1), and one Si(2) atom to form OLi2FeSi trigonal pyramids that share  a cornercorner with one O(4)LiFe2Si tetrahedra,  a cornercorner with one O(5)LiFe2Si trigonal pyramid,  an edgeedge with one O(4)LiFe2Si tetrahedra,  an edgeedge with one O(1)Li2FeSi trigonal pyramid, and  an edgeedge with one O(5)LiFe2Si trigonal pyramid. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded to one Li(1), one Fe(1), one Fe(3), and one Si(1) atom to form distorted OLiFe2Si tetrahedra that share  a cornercorner with one O(1)Li2FeSi trigonal pyramid, corners with two equivalent O(5)LiFe2Si trigonal pyramids, and  an edgeedge with one O(1)Li2FeSi trigonal pyramid. In the fifth O site, O(5) is bonded to one Li(1), one Fe(2), one Fe(3), and one Si(2) atom to form distorted OLiFe2Si trigonal pyramids that share corners with two equivalent O(4)LiFe2Si tetrahedra,  a cornercorner with one O(1)Li2FeSi trigonal pyramid,  a cornercorner with one O(5)LiFe2Si trigonal pyramid, and  an edgeedge with one O(1)Li2FeSi trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Fe(3) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Si(1) atom. is represented by the CIF card [CIF]
data_Li2Fe5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.544
_cell_length_b   7.567
_cell_length_c   8.112
_cell_angle_alpha   114.829
_cell_angle_beta   91.546
_cell_angle_gamma   104.392
_symmetry_Int_Tables_number   1
_cell_volume   295.820
_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  0.231  0.101  0.455  1.0
  Li  Li1  1  0.769  0.899  0.545  1.0
  Fe  Fe2  1  0.074  0.388  0.810  1.0
  Fe  Fe3  1  0.926  0.612  0.190  1.0
  Fe  Fe4  1  0.000  1.000  0.000  1.0
  Fe  Fe5  1  0.636  0.583  0.705  1.0
  Fe  Fe6  1  0.364  0.417  0.295  1.0
  Si  Si7  1  0.500  0.223  0.863  1.0
  Si  Si8  1  0.500  0.777  0.137  1.0
  Si  Si9  1  0.789  0.210  0.392  1.0
  Si  Si10  1  0.211  0.790  0.608  1.0
  O  O11  1  0.884  0.180  0.568  1.0
  O  O12  1  0.116  0.820  0.432  1.0
  O  O13  1  0.792  0.339  0.961  1.0
  O  O14  1  0.208  0.661  0.039  1.0
  O  O15  1  0.528  0.019  0.277  1.0
  O  O16  1  0.472  0.981  0.723  1.0
  O  O17  1  0.408  0.326  0.736  1.0
  O  O18  1  0.592  0.674  0.263  1.0
  O  O19  1  0.022  0.186  0.268  1.0
  O  O20  1  0.978  0.814  0.732  1.0
  O  O21  1  0.696  0.412  0.439  1.0
  O  O22  1  0.304  0.588  0.561  1.0
  O  O23  1  0.313  0.227  0.017  1.0
  O  O24  1  0.687  0.773  0.983  1.0
[/CIF]
.