The compound described by Li2Cr2H4O9 crystallizes in the monoclinic C2/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form LiO6 octahedra that share corners with four equivalent Cr(1)O4 tetrahedra and corners with two equivalent Li(2)O5 trigonal bipyramids. In the second Li site, Li(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(5) atoms to form LiO5 trigonal bipyramids that share corners with two equivalent Li(1)O6 octahedra and corners with four equivalent Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share corners with two equivalent Li(1)O6 octahedra,  a cornercorner with one Cr(1)O4 tetrahedra, and corners with two equivalent Li(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 20-41°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(2) and two equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Li(2) and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Li(1) and one Cr(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Li(1) and one Cr(1) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one H(1), and one H(2) atom to form distorted corner-sharing OLi2H2 tetrahedra. is represented by the CIF card [CIF]
data_Li2Cr2H4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.466
_cell_length_b   5.466
_cell_length_c   12.973
_cell_angle_alpha   85.577
_cell_angle_beta   85.577
_cell_angle_gamma   91.715
_symmetry_Int_Tables_number   1
_cell_volume   385.106
_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  0.500  0.000  0.500  1.0
  Li  Li1  1  0.000  0.500  0.000  1.0
  Li  Li2  1  0.223  0.777  0.750  1.0
  Li  Li3  1  0.777  0.223  0.250  1.0
  Cr  Cr4  1  0.739  0.011  0.860  1.0
  Cr  Cr5  1  0.011  0.739  0.360  1.0
  Cr  Cr6  1  0.261  0.989  0.140  1.0
  Cr  Cr7  1  0.989  0.261  0.640  1.0
  H  H8  1  0.419  0.579  0.599  1.0
  H  H9  1  0.579  0.419  0.099  1.0
  H  H10  1  0.581  0.421  0.401  1.0
  H  H11  1  0.421  0.581  0.901  1.0
  H  H12  1  0.634  0.701  0.650  1.0
  H  H13  1  0.701  0.634  0.150  1.0
  H  H14  1  0.366  0.299  0.350  1.0
  H  H15  1  0.299  0.366  0.850  1.0
  O  O16  1  0.965  0.035  0.750  1.0
  O  O17  1  0.035  0.965  0.250  1.0
  O  O18  1  0.467  0.058  0.819  1.0
  O  O19  1  0.058  0.467  0.319  1.0
  O  O20  1  0.533  0.942  0.181  1.0
  O  O21  1  0.942  0.533  0.681  1.0
  O  O22  1  0.746  0.734  0.917  1.0
  O  O23  1  0.734  0.746  0.417  1.0
  O  O24  1  0.254  0.266  0.083  1.0
  O  O25  1  0.266  0.254  0.583  1.0
  O  O26  1  0.786  0.192  0.561  1.0
  O  O27  1  0.192  0.786  0.061  1.0
  O  O28  1  0.214  0.808  0.439  1.0
  O  O29  1  0.808  0.214  0.939  1.0
  O  O30  1  0.468  0.731  0.630  1.0
  O  O31  1  0.731  0.468  0.130  1.0
  O  O32  1  0.532  0.269  0.370  1.0
  O  O33  1  0.269  0.532  0.870  1.0
[/CIF]
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The compound described by Li2Cr2H4O9 crystallizes in the monoclinic C2/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form LiO6 octahedra that share corners with four equivalent Cr(1)O4 tetrahedra and corners with two equivalent Li(2)O5 trigonal bipyramids. In the second Li site, Li(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(5) atoms to form LiO5 trigonal bipyramids that share corners with two equivalent Li(1)O6 octahedra and corners with four equivalent Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share corners with two equivalent Li(1)O6 octahedra,  a cornercorner with one Cr(1)O4 tetrahedra, and corners with two equivalent Li(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 20-41°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(2) and two equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Li(2) and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Li(1) and one Cr(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Li(1) and one Cr(1) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one H(1), and one H(2) atom to form distorted corner-sharing OLi2H2 tetrahedra. is represented by the CIF card [CIF]
data_Li2Cr2H4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.466
_cell_length_b   5.466
_cell_length_c   12.973
_cell_angle_alpha   85.577
_cell_angle_beta   85.577
_cell_angle_gamma   91.715
_symmetry_Int_Tables_number   1
_cell_volume   385.106
_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  0.500  0.000  0.500  1.0
  Li  Li1  1  0.000  0.500  0.000  1.0
  Li  Li2  1  0.223  0.777  0.750  1.0
  Li  Li3  1  0.777  0.223  0.250  1.0
  Cr  Cr4  1  0.739  0.011  0.860  1.0
  Cr  Cr5  1  0.011  0.739  0.360  1.0
  Cr  Cr6  1  0.261  0.989  0.140  1.0
  Cr  Cr7  1  0.989  0.261  0.640  1.0
  H  H8  1  0.419  0.579  0.599  1.0
  H  H9  1  0.579  0.419  0.099  1.0
  H  H10  1  0.581  0.421  0.401  1.0
  H  H11  1  0.421  0.581  0.901  1.0
  H  H12  1  0.634  0.701  0.650  1.0
  H  H13  1  0.701  0.634  0.150  1.0
  H  H14  1  0.366  0.299  0.350  1.0
  H  H15  1  0.299  0.366  0.850  1.0
  O  O16  1  0.965  0.035  0.750  1.0
  O  O17  1  0.035  0.965  0.250  1.0
  O  O18  1  0.467  0.058  0.819  1.0
  O  O19  1  0.058  0.467  0.319  1.0
  O  O20  1  0.533  0.942  0.181  1.0
  O  O21  1  0.942  0.533  0.681  1.0
  O  O22  1  0.746  0.734  0.917  1.0
  O  O23  1  0.734  0.746  0.417  1.0
  O  O24  1  0.254  0.266  0.083  1.0
  O  O25  1  0.266  0.254  0.583  1.0
  O  O26  1  0.786  0.192  0.561  1.0
  O  O27  1  0.192  0.786  0.061  1.0
  O  O28  1  0.214  0.808  0.439  1.0
  O  O29  1  0.808  0.214  0.939  1.0
  O  O30  1  0.468  0.731  0.630  1.0
  O  O31  1  0.731  0.468  0.130  1.0
  O  O32  1  0.532  0.269  0.370  1.0
  O  O33  1  0.269  0.532  0.870  1.0
[/CIF]
.