The material described by LiCr(Si2O5)2 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted trigonal non-coplanar geometry to one O(12), one O(7), and one O(9) atom. In the second Li site, Li(2) is bonded to one O(13), one O(17), one O(18), one O(20), and one O(4) atom to form distorted LiO5 square pyramids that share  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra,  an edgeedge with one Si(6)O4 tetrahedra, and  an edgeedge with one Si(7)O4 tetrahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(11), one O(12), one O(7), and one O(8) atom to form 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,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Cr(2)O5 square pyramid. In the second Cr site, Cr(2) is bonded to one O(10), one O(11), one O(13), one O(14), and one O(9) atom to form CrO5 square pyramids that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  an edgeedge with one Cr(1)O5 trigonal bipyramid. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(20), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  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 Cr(1)O5 trigonal bipyramid. In the fifth Si site, Si(5) is bonded to one O(11), one O(15), one O(16), and one O(17) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(6)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the sixth Si site, Si(6) is bonded to one O(12), one O(17), one O(18), and one O(19) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra,  a cornercorner with one Cr(1)O5 trigonal bipyramid, and  an edgeedge with one Li(2)O5 square pyramid. In the seventh Si site, Si(7) is bonded to one O(13), one O(15), one O(19), and one O(20) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Li(2)O5 square pyramid. In the eighth Si site, Si(8) is bonded to one O(1), one O(14), one O(16), and one O(18) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(8) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(2), one Si(3), and one Si(4) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Cr(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Si(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Cr(2), and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(2), and one Si(5) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Li(1), one Cr(1), and one Si(6) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Li(2), one Cr(2), and one Si(7) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Cr(2) and one Si(8) atom. In the fifteenth O site, O(15) is bonded in a bent 120 degrees geometry to one Si(5) and one Si(7) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Si(5) and one Si(8) atom. In the seventeenth O site, O(17) is bonded in a distorted T-shaped geometry to one Li(2), one Si(5), and one Si(6) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(6), and one Si(8) atom. In the nineteenth O site, O(19) is bonded in a bent 150 degrees geometry to one Si(6) and one Si(7) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(1), and one Si(7) atom. is represented by the CIF file [CIF]
data_LiCr(Si2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.091
_cell_length_b   7.420
_cell_length_c   9.629
_cell_angle_alpha   99.072
_cell_angle_beta   103.505
_cell_angle_gamma   116.690
_symmetry_Int_Tables_number   1
_cell_volume   419.490
_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  0.826  0.332  0.431  1.0
  Li  Li1  1  0.604  0.738  0.956  1.0
  Cr  Cr2  1  0.253  0.320  0.430  1.0
  Cr  Cr3  1  0.746  0.685  0.573  1.0
  Si  Si4  1  0.906  0.281  0.138  1.0
  Si  Si5  1  0.240  0.951  0.193  1.0
  Si  Si6  1  0.792  0.606  0.234  1.0
  Si  Si7  1  0.394  0.643  0.246  1.0
  Si  Si8  1  0.609  0.359  0.752  1.0
  Si  Si9  1  0.196  0.385  0.760  1.0
  Si  Si10  1  0.759  0.049  0.810  1.0
  Si  Si11  1  0.096  0.727  0.859  1.0
  O  O12  1  0.214  0.919  0.015  1.0
  O  O13  1  0.995  0.797  0.204  1.0
  O  O14  1  0.738  0.378  0.130  1.0
  O  O15  1  0.579  0.643  0.169  1.0
  O  O16  1  0.145  0.459  0.132  1.0
  O  O17  1  0.417  0.875  0.267  1.0
  O  O18  1  0.951  0.227  0.295  1.0
  O  O19  1  0.336  0.193  0.282  1.0
  O  O20  1  0.839  0.605  0.406  1.0
  O  O21  1  0.444  0.604  0.412  1.0
  O  O22  1  0.564  0.395  0.584  1.0
  O  O23  1  0.113  0.342  0.581  1.0
  O  O24  1  0.667  0.804  0.735  1.0
  O  O25  1  0.041  0.787  0.707  1.0
  O  O26  1  0.585  0.127  0.738  1.0
  O  O27  1  0.861  0.539  0.866  1.0
  O  O28  1  0.434  0.389  0.825  1.0
  O  O29  1  0.263  0.624  0.858  1.0
  O  O30  1  0.004  0.204  0.802  1.0
  O  O31  1  0.783  0.070  0.990  1.0
[/CIF]
.
The material described by LiCr(Si2O5)2 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted trigonal non-coplanar geometry to one O(12), one O(7), and one O(9) atom. In the second Li site, Li(2) is bonded to one O(13), one O(17), one O(18), one O(20), and one O(4) atom to form distorted LiO5 square pyramids that share  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra,  an edgeedge with one Si(6)O4 tetrahedra, and  an edgeedge with one Si(7)O4 tetrahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(11), one O(12), one O(7), and one O(8) atom to form 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,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Cr(2)O5 square pyramid. In the second Cr site, Cr(2) is bonded to one O(10), one O(11), one O(13), one O(14), and one O(9) atom to form CrO5 square pyramids that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  an edgeedge with one Cr(1)O5 trigonal bipyramid. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(20), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  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 Cr(1)O5 trigonal bipyramid. In the fifth Si site, Si(5) is bonded to one O(11), one O(15), one O(16), and one O(17) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(6)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  a cornercorner with one Cr(1)O5 trigonal bipyramid. In the sixth Si site, Si(6) is bonded to one O(12), one O(17), one O(18), and one O(19) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra,  a cornercorner with one Cr(1)O5 trigonal bipyramid, and  an edgeedge with one Li(2)O5 square pyramid. In the seventh Si site, Si(7) is bonded to one O(13), one O(15), one O(19), and one O(20) atom to form SiO4 tetrahedra that share  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Li(2)O5 square pyramid. In the eighth Si site, Si(8) is bonded to one O(1), one O(14), one O(16), and one O(18) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(8) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(2), one Si(3), and one Si(4) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Cr(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Si(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Cr(2), and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Cr(1), one Cr(2), and one Si(5) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Li(1), one Cr(1), and one Si(6) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Li(2), one Cr(2), and one Si(7) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Cr(2) and one Si(8) atom. In the fifteenth O site, O(15) is bonded in a bent 120 degrees geometry to one Si(5) and one Si(7) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Si(5) and one Si(8) atom. In the seventeenth O site, O(17) is bonded in a distorted T-shaped geometry to one Li(2), one Si(5), and one Si(6) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(6), and one Si(8) atom. In the nineteenth O site, O(19) is bonded in a bent 150 degrees geometry to one Si(6) and one Si(7) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(1), and one Si(7) atom. is represented by the CIF file [CIF]
data_LiCr(Si2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.091
_cell_length_b   7.420
_cell_length_c   9.629
_cell_angle_alpha   99.072
_cell_angle_beta   103.505
_cell_angle_gamma   116.690
_symmetry_Int_Tables_number   1
_cell_volume   419.490
_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  0.826  0.332  0.431  1.0
  Li  Li1  1  0.604  0.738  0.956  1.0
  Cr  Cr2  1  0.253  0.320  0.430  1.0
  Cr  Cr3  1  0.746  0.685  0.573  1.0
  Si  Si4  1  0.906  0.281  0.138  1.0
  Si  Si5  1  0.240  0.951  0.193  1.0
  Si  Si6  1  0.792  0.606  0.234  1.0
  Si  Si7  1  0.394  0.643  0.246  1.0
  Si  Si8  1  0.609  0.359  0.752  1.0
  Si  Si9  1  0.196  0.385  0.760  1.0
  Si  Si10  1  0.759  0.049  0.810  1.0
  Si  Si11  1  0.096  0.727  0.859  1.0
  O  O12  1  0.214  0.919  0.015  1.0
  O  O13  1  0.995  0.797  0.204  1.0
  O  O14  1  0.738  0.378  0.130  1.0
  O  O15  1  0.579  0.643  0.169  1.0
  O  O16  1  0.145  0.459  0.132  1.0
  O  O17  1  0.417  0.875  0.267  1.0
  O  O18  1  0.951  0.227  0.295  1.0
  O  O19  1  0.336  0.193  0.282  1.0
  O  O20  1  0.839  0.605  0.406  1.0
  O  O21  1  0.444  0.604  0.412  1.0
  O  O22  1  0.564  0.395  0.584  1.0
  O  O23  1  0.113  0.342  0.581  1.0
  O  O24  1  0.667  0.804  0.735  1.0
  O  O25  1  0.041  0.787  0.707  1.0
  O  O26  1  0.585  0.127  0.738  1.0
  O  O27  1  0.861  0.539  0.866  1.0
  O  O28  1  0.434  0.389  0.825  1.0
  O  O29  1  0.263  0.624  0.858  1.0
  O  O30  1  0.004  0.204  0.802  1.0
  O  O31  1  0.783  0.070  0.990  1.0
[/CIF]
.