The material described by LiFeSi2O6 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(6) atom to form distorted LiO5 square pyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with three equivalent Fe(1)O6 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. Fe(1) is bonded to one O(1), one O(6), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Li(1)O5 square pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(5), one O(6), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, corners with two equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 32-59°. In the second Si site, Si(2) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-60°. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(1), and one Si(1) atom. In the second O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Fe(1), and one Si(2) atom. In the third O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Li(1) and two equivalent Si(1) atoms. In the fifth O site, O(4) is bonded to one Li(1), two equivalent Fe(1), and one Si(2) atom to form distorted corner-sharing OLiFe2Si trigonal pyramids. In the sixth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), two equivalent Fe(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiFe(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.802
_cell_length_b   5.335
_cell_length_c   9.374
_cell_angle_alpha   78.072
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   430.674
_cell_formula_units_Z   4
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  0.003  0.991  0.248  1.0
  Li  Li1  1  0.503  0.509  0.752  1.0
  Li  Li2  1  0.997  0.009  0.752  1.0
  Li  Li3  1  0.497  0.491  0.248  1.0
  Fe  Fe4  1  0.647  0.988  0.250  1.0
  Fe  Fe5  1  0.853  0.488  0.250  1.0
  Fe  Fe6  1  0.353  0.012  0.750  1.0
  Fe  Fe7  1  0.147  0.512  0.750  1.0
  Si  Si8  1  0.661  0.771  0.952  1.0
  Si  Si9  1  0.661  0.209  0.547  1.0
  Si  Si10  1  0.161  0.291  0.453  1.0
  Si  Si11  1  0.339  0.791  0.453  1.0
  Si  Si12  1  0.839  0.709  0.547  1.0
  Si  Si13  1  0.161  0.729  0.048  1.0
  Si  Si14  1  0.839  0.271  0.952  1.0
  Si  Si15  1  0.339  0.229  0.048  1.0
  O  O16  1  0.497  0.229  0.622  1.0
  O  O17  1  0.771  0.419  0.603  1.0
  O  O18  1  0.271  0.081  0.397  1.0
  O  O19  1  0.229  0.581  0.397  1.0
  O  O20  1  0.729  0.919  0.603  1.0
  O  O21  1  0.234  0.974  0.107  1.0
  O  O22  1  0.734  0.526  0.893  1.0
  O  O23  1  0.766  0.026  0.893  1.0
  O  O24  1  0.266  0.474  0.107  1.0
  O  O25  1  0.836  0.772  0.366  1.0
  O  O26  1  0.997  0.271  0.378  1.0
  O  O27  1  0.503  0.771  0.378  1.0
  O  O28  1  0.334  0.294  0.867  1.0
  O  O29  1  0.834  0.206  0.133  1.0
  O  O30  1  0.666  0.706  0.133  1.0
  O  O31  1  0.166  0.794  0.867  1.0
  O  O32  1  0.164  0.228  0.634  1.0
  O  O33  1  0.336  0.728  0.634  1.0
  O  O34  1  0.993  0.698  0.118  1.0
  O  O35  1  0.664  0.272  0.366  1.0
  O  O36  1  0.507  0.198  0.118  1.0
  O  O37  1  0.007  0.302  0.882  1.0
  O  O38  1  0.493  0.802  0.882  1.0
  O  O39  1  0.003  0.729  0.622  1.0
[/CIF]
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The material described by LiFeSi2O6 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(6) atom to form distorted LiO5 square pyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with three equivalent Fe(1)O6 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. Fe(1) is bonded to one O(1), one O(6), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Li(1)O5 square pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(5), one O(6), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, corners with two equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 32-59°. In the second Si site, Si(2) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-60°. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(1), and one Si(1) atom. In the second O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Fe(1), and one Si(2) atom. In the third O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Li(1) and two equivalent Si(1) atoms. In the fifth O site, O(4) is bonded to one Li(1), two equivalent Fe(1), and one Si(2) atom to form distorted corner-sharing OLiFe2Si trigonal pyramids. In the sixth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), two equivalent Fe(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiFe(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.802
_cell_length_b   5.335
_cell_length_c   9.374
_cell_angle_alpha   78.072
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   430.674
_cell_formula_units_Z   4
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  0.003  0.991  0.248  1.0
  Li  Li1  1  0.503  0.509  0.752  1.0
  Li  Li2  1  0.997  0.009  0.752  1.0
  Li  Li3  1  0.497  0.491  0.248  1.0
  Fe  Fe4  1  0.647  0.988  0.250  1.0
  Fe  Fe5  1  0.853  0.488  0.250  1.0
  Fe  Fe6  1  0.353  0.012  0.750  1.0
  Fe  Fe7  1  0.147  0.512  0.750  1.0
  Si  Si8  1  0.661  0.771  0.952  1.0
  Si  Si9  1  0.661  0.209  0.547  1.0
  Si  Si10  1  0.161  0.291  0.453  1.0
  Si  Si11  1  0.339  0.791  0.453  1.0
  Si  Si12  1  0.839  0.709  0.547  1.0
  Si  Si13  1  0.161  0.729  0.048  1.0
  Si  Si14  1  0.839  0.271  0.952  1.0
  Si  Si15  1  0.339  0.229  0.048  1.0
  O  O16  1  0.497  0.229  0.622  1.0
  O  O17  1  0.771  0.419  0.603  1.0
  O  O18  1  0.271  0.081  0.397  1.0
  O  O19  1  0.229  0.581  0.397  1.0
  O  O20  1  0.729  0.919  0.603  1.0
  O  O21  1  0.234  0.974  0.107  1.0
  O  O22  1  0.734  0.526  0.893  1.0
  O  O23  1  0.766  0.026  0.893  1.0
  O  O24  1  0.266  0.474  0.107  1.0
  O  O25  1  0.836  0.772  0.366  1.0
  O  O26  1  0.997  0.271  0.378  1.0
  O  O27  1  0.503  0.771  0.378  1.0
  O  O28  1  0.334  0.294  0.867  1.0
  O  O29  1  0.834  0.206  0.133  1.0
  O  O30  1  0.666  0.706  0.133  1.0
  O  O31  1  0.166  0.794  0.867  1.0
  O  O32  1  0.164  0.228  0.634  1.0
  O  O33  1  0.336  0.728  0.634  1.0
  O  O34  1  0.993  0.698  0.118  1.0
  O  O35  1  0.664  0.272  0.366  1.0
  O  O36  1  0.507  0.198  0.118  1.0
  O  O37  1  0.007  0.302  0.882  1.0
  O  O38  1  0.493  0.802  0.882  1.0
  O  O39  1  0.003  0.729  0.622  1.0
[/CIF]
.