The compound described by Li2Cr4Si4O13 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(2), one O(3), one O(4), and one O(5) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Cr(1)O6 octahedra, and  an edgeedge with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 68-77°. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(10), one O(11), one O(12), and one O(9) atom. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form distorted CrO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid,  an edgeedge with one Cr(1)O6 octahedra, edges with three equivalent Cr(2)O6 octahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(6) atoms to form distorted CrO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid,  an edgeedge with one Cr(2)O6 octahedra, edges with three equivalent Cr(1)O6 octahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. In the third Cr site, Cr(3) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(7), one O(9), and two equivalent O(8) atoms. In the fourth Cr site, Cr(4) is bonded in a 5-coordinate geometry to one O(10), one O(4), one O(7), one O(8), and one O(9) atom. There are four 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(9) atom to form SiO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, and corners with three equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 53-56°. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(13), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 53-65°. In the third Si site, Si(3) is bonded to one O(11), one O(12), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra,  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 51-69°. In the fourth Si site, Si(4) is bonded to one O(1), one O(11), one O(13), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra, corners with two equivalent Cr(1)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 55-63°. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Cr(2), two equivalent Cr(1), and one Si(4) atom. In the second O site, O(2) is bonded to one Li(1), one Cr(1), one Cr(2), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLiCr2Si trigonal pyramids. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Li(1), one Cr(2), one Cr(3), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Li(1), one Cr(1), one Cr(4), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLiCr2Si trigonal pyramids. In the fifth O site, O(5) is bonded to one Li(1), one Cr(1), one Cr(2), and one Si(2) atom to form distorted corner-sharing OLiCr2Si tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Cr(1), two equivalent Cr(2), and one Si(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Cr(3), one Cr(4), and one Si(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Cr(4), two equivalent Cr(3), and one Si(3) atom. In the ninth O site, O(9) is bonded to one Li(2), one Cr(3), one Cr(4), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLiCr2Si tetrahedra. In the tenth O site, O(10) is bonded to one Li(2), one Cr(3), one Cr(4), and one Si(2) atom to form distorted corner-sharing OLiCr2Si tetrahedra. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(3), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Li(2), one Si(2), and one Si(3) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF file [CIF]
data_Li2Cr4Si4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.940
_cell_length_b   7.873
_cell_length_c   10.341
_cell_angle_alpha   108.075
_cell_angle_beta   88.281
_cell_angle_gamma   99.800
_symmetry_Int_Tables_number   1
_cell_volume   529.171
_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  0.779  0.598  0.111  1.0
  Li  Li1  1  0.248  0.410  0.412  1.0
  Li  Li2  1  0.752  0.590  0.588  1.0
  Li  Li3  1  0.221  0.402  0.889  1.0
  Cr  Cr4  1  0.082  0.813  0.997  1.0
  Cr  Cr5  1  0.567  0.811  0.007  1.0
  Cr  Cr6  1  0.572  0.789  0.380  1.0
  Cr  Cr7  1  0.069  0.785  0.376  1.0
  Cr  Cr8  1  0.931  0.215  0.624  1.0
  Cr  Cr9  1  0.428  0.211  0.620  1.0
  Cr  Cr10  1  0.433  0.189  0.993  1.0
  Cr  Cr11  1  0.918  0.187  0.003  1.0
  Si  Si12  1  0.277  0.575  0.167  1.0
  Si  Si13  1  0.719  0.392  0.298  1.0
  Si  Si14  1  0.377  0.092  0.277  1.0
  Si  Si15  1  0.928  0.084  0.281  1.0
  Si  Si16  1  0.072  0.916  0.719  1.0
  Si  Si17  1  0.623  0.908  0.723  1.0
  Si  Si18  1  0.281  0.608  0.702  1.0
  Si  Si19  1  0.723  0.425  0.833  1.0
  O  O20  1  0.886  0.003  0.118  1.0
  O  O21  1  0.230  0.362  0.074  1.0
  O  O22  1  0.500  0.668  0.141  1.0
  O  O23  1  0.097  0.682  0.146  1.0
  O  O24  1  0.742  0.357  0.136  1.0
  O  O25  1  0.402  0.011  0.114  1.0
  O  O26  1  0.856  0.946  0.370  1.0
  O  O27  1  0.400  0.972  0.375  1.0
  O  O28  1  0.273  0.609  0.337  1.0
  O  O29  1  0.763  0.605  0.391  1.0
  O  O30  1  0.162  0.150  0.310  1.0
  O  O31  1  0.501  0.303  0.337  1.0
  O  O32  1  0.863  0.283  0.356  1.0
  O  O33  1  0.137  0.717  0.644  1.0
  O  O34  1  0.499  0.697  0.663  1.0
  O  O35  1  0.838  0.850  0.690  1.0
  O  O36  1  0.237  0.395  0.609  1.0
  O  O37  1  0.727  0.391  0.663  1.0
  O  O38  1  0.600  0.028  0.625  1.0
  O  O39  1  0.144  0.054  0.630  1.0
  O  O40  1  0.598  0.989  0.886  1.0
  O  O41  1  0.258  0.643  0.864  1.0
  O  O42  1  0.903  0.318  0.854  1.0
  O  O43  1  0.500  0.332  0.859  1.0
  O  O44  1  0.770  0.638  0.926  1.0
  O  O45  1  0.114  0.997  0.882  1.0
[/CIF]
.
The compound described by Li2Cr4Si4O13 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(2), one O(3), one O(4), and one O(5) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Cr(1)O6 octahedra, and  an edgeedge with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 68-77°. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(10), one O(11), one O(12), and one O(9) atom. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form distorted CrO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid,  an edgeedge with one Cr(1)O6 octahedra, edges with three equivalent Cr(2)O6 octahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(6) atoms to form distorted CrO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid,  an edgeedge with one Cr(2)O6 octahedra, edges with three equivalent Cr(1)O6 octahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. In the third Cr site, Cr(3) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(7), one O(9), and two equivalent O(8) atoms. In the fourth Cr site, Cr(4) is bonded in a 5-coordinate geometry to one O(10), one O(4), one O(7), one O(8), and one O(9) atom. There are four 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(9) atom to form SiO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, and corners with three equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 53-56°. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(13), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 53-65°. In the third Si site, Si(3) is bonded to one O(11), one O(12), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra,  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 51-69°. In the fourth Si site, Si(4) is bonded to one O(1), one O(11), one O(13), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra, corners with two equivalent Cr(1)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 55-63°. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Cr(2), two equivalent Cr(1), and one Si(4) atom. In the second O site, O(2) is bonded to one Li(1), one Cr(1), one Cr(2), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLiCr2Si trigonal pyramids. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Li(1), one Cr(2), one Cr(3), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Li(1), one Cr(1), one Cr(4), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLiCr2Si trigonal pyramids. In the fifth O site, O(5) is bonded to one Li(1), one Cr(1), one Cr(2), and one Si(2) atom to form distorted corner-sharing OLiCr2Si tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Cr(1), two equivalent Cr(2), and one Si(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Cr(3), one Cr(4), and one Si(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Cr(4), two equivalent Cr(3), and one Si(3) atom. In the ninth O site, O(9) is bonded to one Li(2), one Cr(3), one Cr(4), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLiCr2Si tetrahedra. In the tenth O site, O(10) is bonded to one Li(2), one Cr(3), one Cr(4), and one Si(2) atom to form distorted corner-sharing OLiCr2Si tetrahedra. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(3), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Li(2), one Si(2), and one Si(3) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF file [CIF]
data_Li2Cr4Si4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.940
_cell_length_b   7.873
_cell_length_c   10.341
_cell_angle_alpha   108.075
_cell_angle_beta   88.281
_cell_angle_gamma   99.800
_symmetry_Int_Tables_number   1
_cell_volume   529.171
_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  0.779  0.598  0.111  1.0
  Li  Li1  1  0.248  0.410  0.412  1.0
  Li  Li2  1  0.752  0.590  0.588  1.0
  Li  Li3  1  0.221  0.402  0.889  1.0
  Cr  Cr4  1  0.082  0.813  0.997  1.0
  Cr  Cr5  1  0.567  0.811  0.007  1.0
  Cr  Cr6  1  0.572  0.789  0.380  1.0
  Cr  Cr7  1  0.069  0.785  0.376  1.0
  Cr  Cr8  1  0.931  0.215  0.624  1.0
  Cr  Cr9  1  0.428  0.211  0.620  1.0
  Cr  Cr10  1  0.433  0.189  0.993  1.0
  Cr  Cr11  1  0.918  0.187  0.003  1.0
  Si  Si12  1  0.277  0.575  0.167  1.0
  Si  Si13  1  0.719  0.392  0.298  1.0
  Si  Si14  1  0.377  0.092  0.277  1.0
  Si  Si15  1  0.928  0.084  0.281  1.0
  Si  Si16  1  0.072  0.916  0.719  1.0
  Si  Si17  1  0.623  0.908  0.723  1.0
  Si  Si18  1  0.281  0.608  0.702  1.0
  Si  Si19  1  0.723  0.425  0.833  1.0
  O  O20  1  0.886  0.003  0.118  1.0
  O  O21  1  0.230  0.362  0.074  1.0
  O  O22  1  0.500  0.668  0.141  1.0
  O  O23  1  0.097  0.682  0.146  1.0
  O  O24  1  0.742  0.357  0.136  1.0
  O  O25  1  0.402  0.011  0.114  1.0
  O  O26  1  0.856  0.946  0.370  1.0
  O  O27  1  0.400  0.972  0.375  1.0
  O  O28  1  0.273  0.609  0.337  1.0
  O  O29  1  0.763  0.605  0.391  1.0
  O  O30  1  0.162  0.150  0.310  1.0
  O  O31  1  0.501  0.303  0.337  1.0
  O  O32  1  0.863  0.283  0.356  1.0
  O  O33  1  0.137  0.717  0.644  1.0
  O  O34  1  0.499  0.697  0.663  1.0
  O  O35  1  0.838  0.850  0.690  1.0
  O  O36  1  0.237  0.395  0.609  1.0
  O  O37  1  0.727  0.391  0.663  1.0
  O  O38  1  0.600  0.028  0.625  1.0
  O  O39  1  0.144  0.054  0.630  1.0
  O  O40  1  0.598  0.989  0.886  1.0
  O  O41  1  0.258  0.643  0.864  1.0
  O  O42  1  0.903  0.318  0.854  1.0
  O  O43  1  0.500  0.332  0.859  1.0
  O  O44  1  0.770  0.638  0.926  1.0
  O  O45  1  0.114  0.997  0.882  1.0
[/CIF]
.