The material structure described by Li2Cr5(Si2O7)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(5), one O(7), one O(9), 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(3)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid,  an edgeedge with one Si(3)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded to one O(10), one O(6), one O(8), and two equivalent O(2) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid,  an edgeedge with one Si(4)O4 tetrahedra, and  an edgeedge with one Li(2)O5 trigonal bipyramid. There are six inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a square co-planar geometry to two equivalent O(10) and two equivalent O(14) atoms. In the second Cr site, Cr(2) is bonded in a rectangular see-saw-like geometry to one O(1), one O(3), one O(4), and one O(7) atom. In the third Cr site, Cr(3) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(4), and one O(8) atom. In the fourth Cr site, Cr(4) is bonded in a square co-planar geometry to two equivalent O(13) and two equivalent O(9) atoms. In the fifth Cr site, Cr(5) is bonded to one O(10), one O(11), one O(12), one O(14), and one O(7) atom to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid,  a cornercorner with one Li(2)O5 trigonal bipyramid, and  an edgeedge with one Cr(6)O5 trigonal bipyramid. In the sixth Cr site, Cr(6) is bonded to one O(11), one O(12), one O(13), one O(8), and one O(9) atom to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid,  a cornercorner with one Li(2)O5 trigonal bipyramid, and  an edgeedge with one Cr(5)O5 trigonal bipyramid. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(13), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid, and corners with two equivalent Li(1)O5 trigonal bipyramids. In the second Si site, Si(2) is bonded to one O(14), one O(4), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid, and corners with two equivalent Li(2)O5 trigonal bipyramids. In the third Si site, Si(3) is bonded to one O(1), one O(11), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid, corners with two equivalent Li(1)O5 trigonal bipyramids, corners with two equivalent Cr(6)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. In the fourth Si site, Si(4) is bonded to one O(10), one O(12), one O(2), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Cr(6)O5 trigonal bipyramid, corners with two equivalent Li(2)O5 trigonal bipyramids, corners with two equivalent Cr(5)O5 trigonal bipyramids, and  an edgeedge with one Li(2)O5 trigonal bipyramid. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Cr(2), and one Si(3) atom to form OLi2CrSi trigonal pyramids that share  a cornercorner with one O(7)LiCr2Si tetrahedra,  a cornercorner with one O(9)LiCr2Si trigonal pyramid,  an edgeedge with one O(7)LiCr2Si tetrahedra,  an edgeedge with one O(1)Li2CrSi trigonal pyramid, and  an edgeedge with one O(9)LiCr2Si trigonal pyramid. In the second O site, O(2) is bonded to two equivalent Li(2), one Cr(3), and one Si(4) atom to form OLi2CrSi trigonal pyramids that share  a cornercorner with one O(8)LiCr2Si tetrahedra,  a cornercorner with one O(10)LiCr2Si trigonal pyramid,  an edgeedge with one O(8)LiCr2Si tetrahedra,  an edgeedge with one O(2)Li2CrSi trigonal pyramid, and  an edgeedge with one O(10)LiCr2Si trigonal pyramid. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(2), and one Si(4) atom. In the seventh O site, O(7) is bonded to one Li(1), one Cr(2), one Cr(5), and one Si(1) atom to form OLiCr2Si tetrahedra that share  a cornercorner with one O(1)Li2CrSi trigonal pyramid,  a cornercorner with one O(10)LiCr2Si trigonal pyramid,  a cornercorner with one O(9)LiCr2Si trigonal pyramid, and  an edgeedge with one O(1)Li2CrSi trigonal pyramid. In the eighth O site, O(8) is bonded to one Li(2), one Cr(3), one Cr(6), and one Si(2) atom to form OLiCr2Si tetrahedra that share  a cornercorner with one O(2)Li2CrSi trigonal pyramid,  a cornercorner with one O(10)LiCr2Si trigonal pyramid,  a cornercorner with one O(9)LiCr2Si trigonal pyramid, and  an edgeedge with one O(2)Li2CrSi trigonal pyramid. In the ninth O site, O(9) is bonded to one Li(1), one Cr(4), one Cr(6), and one Si(3) atom to form distorted OLiCr2Si trigonal pyramids that share  a cornercorner with one O(7)LiCr2Si tetrahedra,  a cornercorner with one O(8)LiCr2Si tetrahedra,  a cornercorner with one O(1)Li2CrSi trigonal pyramid,  a cornercorner with one O(9)LiCr2Si trigonal pyramid, and  an edgeedge with one O(1)Li2CrSi trigonal pyramid. In the tenth O site, O(10) is bonded to one Li(2), one Cr(1), one Cr(5), and one Si(4) atom to form distorted OLiCr2Si trigonal pyramids that share  a cornercorner with one O(7)LiCr2Si tetrahedra,  a cornercorner with one O(8)LiCr2Si tetrahedra,  a cornercorner with one O(2)Li2CrSi trigonal pyramid,  a cornercorner with one O(10)LiCr2Si trigonal pyramid, and  an edgeedge with one O(2)Li2CrSi trigonal pyramid. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Cr(5), one Cr(6), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Cr(5), one Cr(6), and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Cr(4), one Cr(6), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(5), and one Si(2) atom. is represented by the CIF card [CIF]
data_Li2Cr5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.615
_cell_length_b   7.630
_cell_length_c   8.041
_cell_angle_alpha   113.881
_cell_angle_beta   91.206
_cell_angle_gamma   105.779
_symmetry_Int_Tables_number   1
_cell_volume   299.714
_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
  Cr  Cr0  1  1.000  0.000  0.000  1.0
  Cr  Cr1  1  0.074  0.386  0.810  1.0
  Cr  Cr2  1  0.926  0.614  0.190  1.0
  Cr  Cr3  1  0.667  0.571  0.711  1.0
  Cr  Cr4  1  0.333  0.429  0.289  1.0
  Li  Li5  1  0.228  0.110  0.456  1.0
  Li  Li6  1  0.772  0.890  0.544  1.0
  O  O7  1  0.884  0.167  0.567  1.0
  O  O8  1  0.116  0.833  0.433  1.0
  O  O9  1  0.779  0.352  0.953  1.0
  O  O10  1  0.221  0.648  0.047  1.0
  O  O11  1  0.536  0.013  0.271  1.0
  O  O12  1  0.464  0.987  0.729  1.0
  O  O13  1  0.403  0.324  0.724  1.0
  O  O14  1  0.597  0.676  0.276  1.0
  O  O15  1  0.026  0.190  0.271  1.0
  O  O16  1  0.974  0.810  0.729  1.0
  O  O17  1  0.700  0.403  0.444  1.0
  O  O18  1  0.300  0.597  0.556  1.0
  O  O19  1  0.301  0.233  0.011  1.0
  O  O20  1  0.699  0.767  0.989  1.0
  Si  Si21  1  0.491  0.226  0.857  1.0
  Si  Si22  1  0.509  0.774  0.143  1.0
  Si  Si23  1  0.792  0.206  0.394  1.0
  Si  Si24  1  0.208  0.794  0.606  1.0
[/CIF]
.
The material structure described by Li2Cr5(Si2O7)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(5), one O(7), one O(9), 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(3)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid,  an edgeedge with one Si(3)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded to one O(10), one O(6), one O(8), and two equivalent O(2) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid,  an edgeedge with one Si(4)O4 tetrahedra, and  an edgeedge with one Li(2)O5 trigonal bipyramid. There are six inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a square co-planar geometry to two equivalent O(10) and two equivalent O(14) atoms. In the second Cr site, Cr(2) is bonded in a rectangular see-saw-like geometry to one O(1), one O(3), one O(4), and one O(7) atom. In the third Cr site, Cr(3) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(4), and one O(8) atom. In the fourth Cr site, Cr(4) is bonded in a square co-planar geometry to two equivalent O(13) and two equivalent O(9) atoms. In the fifth Cr site, Cr(5) is bonded to one O(10), one O(11), one O(12), one O(14), and one O(7) atom to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid,  a cornercorner with one Li(2)O5 trigonal bipyramid, and  an edgeedge with one Cr(6)O5 trigonal bipyramid. In the sixth Cr site, Cr(6) is bonded to one O(11), one O(12), one O(13), one O(8), and one O(9) atom to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid,  a cornercorner with one Li(2)O5 trigonal bipyramid, and  an edgeedge with one Cr(5)O5 trigonal bipyramid. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(13), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid, and corners with two equivalent Li(1)O5 trigonal bipyramids. In the second Si site, Si(2) is bonded to one O(14), one O(4), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid,  a cornercorner with one Cr(6)O5 trigonal bipyramid, and corners with two equivalent Li(2)O5 trigonal bipyramids. In the third Si site, Si(3) is bonded to one O(1), one O(11), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Cr(5)O5 trigonal bipyramid, corners with two equivalent Li(1)O5 trigonal bipyramids, corners with two equivalent Cr(6)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. In the fourth Si site, Si(4) is bonded to one O(10), one O(12), one O(2), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Cr(6)O5 trigonal bipyramid, corners with two equivalent Li(2)O5 trigonal bipyramids, corners with two equivalent Cr(5)O5 trigonal bipyramids, and  an edgeedge with one Li(2)O5 trigonal bipyramid. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Cr(2), and one Si(3) atom to form OLi2CrSi trigonal pyramids that share  a cornercorner with one O(7)LiCr2Si tetrahedra,  a cornercorner with one O(9)LiCr2Si trigonal pyramid,  an edgeedge with one O(7)LiCr2Si tetrahedra,  an edgeedge with one O(1)Li2CrSi trigonal pyramid, and  an edgeedge with one O(9)LiCr2Si trigonal pyramid. In the second O site, O(2) is bonded to two equivalent Li(2), one Cr(3), and one Si(4) atom to form OLi2CrSi trigonal pyramids that share  a cornercorner with one O(8)LiCr2Si tetrahedra,  a cornercorner with one O(10)LiCr2Si trigonal pyramid,  an edgeedge with one O(8)LiCr2Si tetrahedra,  an edgeedge with one O(2)Li2CrSi trigonal pyramid, and  an edgeedge with one O(10)LiCr2Si trigonal pyramid. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(2), and one Si(4) atom. In the seventh O site, O(7) is bonded to one Li(1), one Cr(2), one Cr(5), and one Si(1) atom to form OLiCr2Si tetrahedra that share  a cornercorner with one O(1)Li2CrSi trigonal pyramid,  a cornercorner with one O(10)LiCr2Si trigonal pyramid,  a cornercorner with one O(9)LiCr2Si trigonal pyramid, and  an edgeedge with one O(1)Li2CrSi trigonal pyramid. In the eighth O site, O(8) is bonded to one Li(2), one Cr(3), one Cr(6), and one Si(2) atom to form OLiCr2Si tetrahedra that share  a cornercorner with one O(2)Li2CrSi trigonal pyramid,  a cornercorner with one O(10)LiCr2Si trigonal pyramid,  a cornercorner with one O(9)LiCr2Si trigonal pyramid, and  an edgeedge with one O(2)Li2CrSi trigonal pyramid. In the ninth O site, O(9) is bonded to one Li(1), one Cr(4), one Cr(6), and one Si(3) atom to form distorted OLiCr2Si trigonal pyramids that share  a cornercorner with one O(7)LiCr2Si tetrahedra,  a cornercorner with one O(8)LiCr2Si tetrahedra,  a cornercorner with one O(1)Li2CrSi trigonal pyramid,  a cornercorner with one O(9)LiCr2Si trigonal pyramid, and  an edgeedge with one O(1)Li2CrSi trigonal pyramid. In the tenth O site, O(10) is bonded to one Li(2), one Cr(1), one Cr(5), and one Si(4) atom to form distorted OLiCr2Si trigonal pyramids that share  a cornercorner with one O(7)LiCr2Si tetrahedra,  a cornercorner with one O(8)LiCr2Si tetrahedra,  a cornercorner with one O(2)Li2CrSi trigonal pyramid,  a cornercorner with one O(10)LiCr2Si trigonal pyramid, and  an edgeedge with one O(2)Li2CrSi trigonal pyramid. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Cr(5), one Cr(6), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Cr(5), one Cr(6), and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Cr(4), one Cr(6), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(5), and one Si(2) atom. is represented by the CIF card [CIF]
data_Li2Cr5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.615
_cell_length_b   7.630
_cell_length_c   8.041
_cell_angle_alpha   113.881
_cell_angle_beta   91.206
_cell_angle_gamma   105.779
_symmetry_Int_Tables_number   1
_cell_volume   299.714
_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
  Cr  Cr0  1  1.000  0.000  0.000  1.0
  Cr  Cr1  1  0.074  0.386  0.810  1.0
  Cr  Cr2  1  0.926  0.614  0.190  1.0
  Cr  Cr3  1  0.667  0.571  0.711  1.0
  Cr  Cr4  1  0.333  0.429  0.289  1.0
  Li  Li5  1  0.228  0.110  0.456  1.0
  Li  Li6  1  0.772  0.890  0.544  1.0
  O  O7  1  0.884  0.167  0.567  1.0
  O  O8  1  0.116  0.833  0.433  1.0
  O  O9  1  0.779  0.352  0.953  1.0
  O  O10  1  0.221  0.648  0.047  1.0
  O  O11  1  0.536  0.013  0.271  1.0
  O  O12  1  0.464  0.987  0.729  1.0
  O  O13  1  0.403  0.324  0.724  1.0
  O  O14  1  0.597  0.676  0.276  1.0
  O  O15  1  0.026  0.190  0.271  1.0
  O  O16  1  0.974  0.810  0.729  1.0
  O  O17  1  0.700  0.403  0.444  1.0
  O  O18  1  0.300  0.597  0.556  1.0
  O  O19  1  0.301  0.233  0.011  1.0
  O  O20  1  0.699  0.767  0.989  1.0
  Si  Si21  1  0.491  0.226  0.857  1.0
  Si  Si22  1  0.509  0.774  0.143  1.0
  Si  Si23  1  0.792  0.206  0.394  1.0
  Si  Si24  1  0.208  0.794  0.606  1.0
[/CIF]
.