The structure described by Li2MnO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Li(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-8°. In the second Li site, Li(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form LiO6 octahedra that share corners with six equivalent Li(3)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. In the third Li site, Li(3) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form LiO6 octahedra that share corners with three equivalent Li(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra,  an edgeedge with one Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with four equivalent Li(3)O6 octahedra, and edges with five equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. Mn(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form MnO6 octahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Li(3)O6 octahedra,  an edgeedge with one Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra, and edges with five equivalent Li(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-10°. There are three inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Li(3) and three equivalent Mn(1) atoms to form OLi3Mn3 octahedra that share corners with three equivalent O(2)Li4Mn2 octahedra, corners with three equivalent O(3)Li5Mn octahedra, edges with three equivalent O(2)Li4Mn2 octahedra, edges with three equivalent O(3)Li5Mn octahedra, and edges with six equivalent O(1)Li3Mn3 octahedra. The corner-sharing octahedral tilt angles range from 7-9°. In the second O site, O(2) is bonded to one Li(2), one Li(3), two equivalent Li(1), and two equivalent Mn(1) atoms to form OLi4Mn2 octahedra that share corners with three equivalent O(1)Li3Mn3 octahedra, corners with three equivalent O(2)Li4Mn2 octahedra, edges with three equivalent O(1)Li3Mn3 octahedra, edges with three equivalent O(2)Li4Mn2 octahedra, and edges with six equivalent O(3)Li5Mn octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the third O site, O(3) is bonded to one Li(1), two equivalent Li(2), two equivalent Li(3), and one Mn(1) atom to form OLi5Mn octahedra that share corners with three equivalent O(1)Li3Mn3 octahedra, corners with three equivalent O(3)Li5Mn octahedra, edges with three equivalent O(1)Li3Mn3 octahedra, edges with three equivalent O(3)Li5Mn octahedra, and edges with six equivalent O(2)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2MnO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.895
_cell_length_b   5.074
_cell_length_c   7.685
_cell_angle_alpha   72.195
_cell_angle_beta   79.154
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   105.371
_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  0.167  0.500  0.667  1.0
  Li  Li1  1  0.667  0.000  0.667  1.0
  Li  Li2  1  0.827  0.480  0.347  1.0
  Li  Li3  1  0.506  0.520  0.987  1.0
  Mn  Mn4  1  0.004  0.996  0.991  1.0
  Mn  Mn5  1  0.329  0.004  0.342  1.0
  O  O6  1  0.423  0.788  0.153  1.0
  O  O7  1  0.910  0.212  0.180  1.0
  O  O8  1  0.761  0.775  0.478  1.0
  O  O9  1  0.572  0.225  0.855  1.0
  O  O10  1  0.075  0.765  0.849  1.0
  O  O11  1  0.258  0.235  0.485  1.0
[/CIF]
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The structure described by Li2MnO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Li(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-8°. In the second Li site, Li(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form LiO6 octahedra that share corners with six equivalent Li(3)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. In the third Li site, Li(3) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form LiO6 octahedra that share corners with three equivalent Li(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra,  an edgeedge with one Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with four equivalent Li(3)O6 octahedra, and edges with five equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. Mn(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form MnO6 octahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Li(3)O6 octahedra,  an edgeedge with one Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra, and edges with five equivalent Li(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-10°. There are three inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Li(3) and three equivalent Mn(1) atoms to form OLi3Mn3 octahedra that share corners with three equivalent O(2)Li4Mn2 octahedra, corners with three equivalent O(3)Li5Mn octahedra, edges with three equivalent O(2)Li4Mn2 octahedra, edges with three equivalent O(3)Li5Mn octahedra, and edges with six equivalent O(1)Li3Mn3 octahedra. The corner-sharing octahedral tilt angles range from 7-9°. In the second O site, O(2) is bonded to one Li(2), one Li(3), two equivalent Li(1), and two equivalent Mn(1) atoms to form OLi4Mn2 octahedra that share corners with three equivalent O(1)Li3Mn3 octahedra, corners with three equivalent O(2)Li4Mn2 octahedra, edges with three equivalent O(1)Li3Mn3 octahedra, edges with three equivalent O(2)Li4Mn2 octahedra, and edges with six equivalent O(3)Li5Mn octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the third O site, O(3) is bonded to one Li(1), two equivalent Li(2), two equivalent Li(3), and one Mn(1) atom to form OLi5Mn octahedra that share corners with three equivalent O(1)Li3Mn3 octahedra, corners with three equivalent O(3)Li5Mn octahedra, edges with three equivalent O(1)Li3Mn3 octahedra, edges with three equivalent O(3)Li5Mn octahedra, and edges with six equivalent O(2)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2MnO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.895
_cell_length_b   5.074
_cell_length_c   7.685
_cell_angle_alpha   72.195
_cell_angle_beta   79.154
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   105.371
_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  0.167  0.500  0.667  1.0
  Li  Li1  1  0.667  0.000  0.667  1.0
  Li  Li2  1  0.827  0.480  0.347  1.0
  Li  Li3  1  0.506  0.520  0.987  1.0
  Mn  Mn4  1  0.004  0.996  0.991  1.0
  Mn  Mn5  1  0.329  0.004  0.342  1.0
  O  O6  1  0.423  0.788  0.153  1.0
  O  O7  1  0.910  0.212  0.180  1.0
  O  O8  1  0.761  0.775  0.478  1.0
  O  O9  1  0.572  0.225  0.855  1.0
  O  O10  1  0.075  0.765  0.849  1.0
  O  O11  1  0.258  0.235  0.485  1.0
[/CIF]
.