The structure described by Li2Cr2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form LiO6 octahedra that share corners with four equivalent Cr(2)O4 tetrahedra, edges with two equivalent Li(1)O6 octahedra, and edges with two equivalent Li(2)O6 pentagonal pyramids. In the second Li site, Li(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted LiO6 pentagonal pyramids that share corners with three equivalent Cr(2)O4 tetrahedra and edges with two equivalent Li(1)O6 octahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. In the second Cr site, Cr(2) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form CrO4 tetrahedra that share corners with four equivalent Li(1)O6 octahedra and corners with three equivalent Li(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 53-60°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Li(1), one Li(2), and one Cr(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(2), one Cr(1), and one Cr(2) atom. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), and one Cr(2) atom to form distorted edge-sharing OLi3Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(2) and two equivalent Cr(1) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Cr(2) atom. is represented by the CIF card [CIF]
data_Li2Cr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.441
_cell_length_b   6.441
_cell_length_c   13.921
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   117.608
_symmetry_Int_Tables_number   1
_cell_volume   511.800
_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  0.245  0.245  0.000  1.0
  Li  Li1  1  0.255  0.255  0.500  1.0
  Li  Li2  1  0.691  0.309  0.358  1.0
  Li  Li3  1  0.809  0.191  0.858  1.0
  Li  Li4  1  0.191  0.809  0.142  1.0
  Li  Li5  1  0.309  0.691  0.642  1.0
  Li  Li6  1  0.745  0.745  0.500  1.0
  Li  Li7  1  0.755  0.755  0.000  1.0
  Cr  Cr8  1  0.173  0.327  0.250  1.0
  Cr  Cr9  1  0.327  0.173  0.750  1.0
  Cr  Cr10  1  0.252  0.748  0.921  1.0
  Cr  Cr11  1  0.748  0.252  0.079  1.0
  Cr  Cr12  1  0.752  0.248  0.579  1.0
  Cr  Cr13  1  0.248  0.752  0.421  1.0
  Cr  Cr14  1  0.827  0.673  0.750  1.0
  Cr  Cr15  1  0.673  0.827  0.250  1.0
  O  O16  1  0.209  0.183  0.161  1.0
  O  O17  1  0.183  0.209  0.839  1.0
  O  O18  1  0.558  0.036  0.149  1.0
  O  O19  1  0.536  0.058  0.649  1.0
  O  O20  1  0.036  0.558  0.851  1.0
  O  O21  1  0.058  0.536  0.351  1.0
  O  O22  1  0.317  0.291  0.339  1.0
  O  O23  1  0.291  0.317  0.661  1.0
  O  O24  1  0.638  0.362  0.499  1.0
  O  O25  1  0.625  0.375  0.783  1.0
  O  O26  1  0.884  0.116  0.525  1.0
  O  O27  1  0.125  0.875  0.717  1.0
  O  O28  1  0.862  0.138  0.999  1.0
  O  O29  1  0.875  0.125  0.283  1.0
  O  O30  1  0.362  0.638  0.501  1.0
  O  O31  1  0.616  0.384  0.025  1.0
  O  O32  1  0.375  0.625  0.217  1.0
  O  O33  1  0.116  0.884  0.475  1.0
  O  O34  1  0.138  0.862  0.001  1.0
  O  O35  1  0.384  0.616  0.975  1.0
  O  O36  1  0.709  0.683  0.339  1.0
  O  O37  1  0.683  0.709  0.661  1.0
  O  O38  1  0.464  0.942  0.351  1.0
  O  O39  1  0.442  0.964  0.851  1.0
  O  O40  1  0.964  0.442  0.149  1.0
  O  O41  1  0.942  0.464  0.649  1.0
  O  O42  1  0.817  0.791  0.161  1.0
  O  O43  1  0.791  0.817  0.839  1.0
[/CIF]
.
The structure described by Li2Cr2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form LiO6 octahedra that share corners with four equivalent Cr(2)O4 tetrahedra, edges with two equivalent Li(1)O6 octahedra, and edges with two equivalent Li(2)O6 pentagonal pyramids. In the second Li site, Li(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted LiO6 pentagonal pyramids that share corners with three equivalent Cr(2)O4 tetrahedra and edges with two equivalent Li(1)O6 octahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. In the second Cr site, Cr(2) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form CrO4 tetrahedra that share corners with four equivalent Li(1)O6 octahedra and corners with three equivalent Li(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 53-60°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Li(1), one Li(2), and one Cr(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(2), one Cr(1), and one Cr(2) atom. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), and one Cr(2) atom to form distorted edge-sharing OLi3Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(2) and two equivalent Cr(1) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Cr(2) atom. is represented by the CIF card [CIF]
data_Li2Cr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.441
_cell_length_b   6.441
_cell_length_c   13.921
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   117.608
_symmetry_Int_Tables_number   1
_cell_volume   511.800
_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  0.245  0.245  0.000  1.0
  Li  Li1  1  0.255  0.255  0.500  1.0
  Li  Li2  1  0.691  0.309  0.358  1.0
  Li  Li3  1  0.809  0.191  0.858  1.0
  Li  Li4  1  0.191  0.809  0.142  1.0
  Li  Li5  1  0.309  0.691  0.642  1.0
  Li  Li6  1  0.745  0.745  0.500  1.0
  Li  Li7  1  0.755  0.755  0.000  1.0
  Cr  Cr8  1  0.173  0.327  0.250  1.0
  Cr  Cr9  1  0.327  0.173  0.750  1.0
  Cr  Cr10  1  0.252  0.748  0.921  1.0
  Cr  Cr11  1  0.748  0.252  0.079  1.0
  Cr  Cr12  1  0.752  0.248  0.579  1.0
  Cr  Cr13  1  0.248  0.752  0.421  1.0
  Cr  Cr14  1  0.827  0.673  0.750  1.0
  Cr  Cr15  1  0.673  0.827  0.250  1.0
  O  O16  1  0.209  0.183  0.161  1.0
  O  O17  1  0.183  0.209  0.839  1.0
  O  O18  1  0.558  0.036  0.149  1.0
  O  O19  1  0.536  0.058  0.649  1.0
  O  O20  1  0.036  0.558  0.851  1.0
  O  O21  1  0.058  0.536  0.351  1.0
  O  O22  1  0.317  0.291  0.339  1.0
  O  O23  1  0.291  0.317  0.661  1.0
  O  O24  1  0.638  0.362  0.499  1.0
  O  O25  1  0.625  0.375  0.783  1.0
  O  O26  1  0.884  0.116  0.525  1.0
  O  O27  1  0.125  0.875  0.717  1.0
  O  O28  1  0.862  0.138  0.999  1.0
  O  O29  1  0.875  0.125  0.283  1.0
  O  O30  1  0.362  0.638  0.501  1.0
  O  O31  1  0.616  0.384  0.025  1.0
  O  O32  1  0.375  0.625  0.217  1.0
  O  O33  1  0.116  0.884  0.475  1.0
  O  O34  1  0.138  0.862  0.001  1.0
  O  O35  1  0.384  0.616  0.975  1.0
  O  O36  1  0.709  0.683  0.339  1.0
  O  O37  1  0.683  0.709  0.661  1.0
  O  O38  1  0.464  0.942  0.351  1.0
  O  O39  1  0.442  0.964  0.851  1.0
  O  O40  1  0.964  0.442  0.149  1.0
  O  O41  1  0.942  0.464  0.649  1.0
  O  O42  1  0.817  0.791  0.161  1.0
  O  O43  1  0.791  0.817  0.839  1.0
[/CIF]
.