The compound described by Li2Fe2B2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(7) atom. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and one O(6) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(6), one O(7), and two equivalent O(3) atoms. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted FeO4 tetrahedra that share corners with two equivalent B(1)O4 tetrahedra and corners with two equivalent B(2)O4 tetrahedra. There are two inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form BO4 tetrahedra that share  a cornercorner with one B(2)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. In the second B site, B(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form BO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Li(2), one Fe(1), one B(1), and one B(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(1), and one B(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Fe(2), two equivalent Fe(1), and one B(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(2), and one B(2) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Fe(2), and one B(2) atom to form corner-sharing OLi2FeB tetrahedra. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one B(2) atom. In the seventh O site, O(7) is bonded to one Li(1), one Fe(1), one Fe(2), and one B(1) atom to form distorted corner-sharing OLiFe2B tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Fe2B2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.128
_cell_length_b   5.290
_cell_length_c   9.459
_cell_angle_alpha   56.517
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   506.148
_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  0.341  0.729  0.126  1.0
  Li  Li1  1  0.745  0.014  0.182  1.0
  Li  Li2  1  0.245  0.986  0.318  1.0
  Li  Li3  1  0.841  0.271  0.374  1.0
  Li  Li4  1  0.159  0.729  0.626  1.0
  Li  Li5  1  0.755  0.014  0.682  1.0
  Li  Li6  1  0.255  0.986  0.818  1.0
  Li  Li7  1  0.659  0.271  0.874  1.0
  Fe  Fe8  1  0.095  0.552  0.106  1.0
  Fe  Fe9  1  0.488  0.186  0.197  1.0
  Fe  Fe10  1  0.988  0.814  0.303  1.0
  Fe  Fe11  1  0.595  0.448  0.394  1.0
  Fe  Fe12  1  0.405  0.552  0.606  1.0
  Fe  Fe13  1  0.012  0.186  0.697  1.0
  Fe  Fe14  1  0.512  0.814  0.803  1.0
  Fe  Fe15  1  0.905  0.448  0.894  1.0
  B  B16  1  0.881  0.780  0.029  1.0
  B  B17  1  0.678  0.626  0.042  1.0
  B  B18  1  0.178  0.374  0.458  1.0
  B  B19  1  0.381  0.220  0.471  1.0
  B  B20  1  0.619  0.780  0.529  1.0
  B  B21  1  0.822  0.626  0.542  1.0
  B  B22  1  0.322  0.374  0.958  1.0
  B  B23  1  0.119  0.220  0.971  1.0
  O  O24  1  0.799  0.567  0.031  1.0
  O  O25  1  0.165  0.939  0.010  1.0
  O  O26  1  0.033  0.197  0.097  1.0
  O  O27  1  0.618  0.356  0.063  1.0
  O  O28  1  0.358  0.098  0.124  1.0
  O  O29  1  0.663  0.672  0.180  1.0
  O  O30  1  0.945  0.608  0.195  1.0
  O  O31  1  0.445  0.392  0.305  1.0
  O  O32  1  0.163  0.328  0.320  1.0
  O  O33  1  0.858  0.902  0.376  1.0
  O  O34  1  0.118  0.644  0.437  1.0
  O  O35  1  0.533  0.803  0.403  1.0
  O  O36  1  0.665  0.061  0.490  1.0
  O  O37  1  0.299  0.433  0.469  1.0
  O  O38  1  0.701  0.567  0.531  1.0
  O  O39  1  0.335  0.939  0.510  1.0
  O  O40  1  0.467  0.197  0.597  1.0
  O  O41  1  0.882  0.356  0.563  1.0
  O  O42  1  0.142  0.098  0.624  1.0
  O  O43  1  0.837  0.672  0.680  1.0
  O  O44  1  0.555  0.608  0.695  1.0
  O  O45  1  0.055  0.392  0.805  1.0
  O  O46  1  0.337  0.328  0.820  1.0
  O  O47  1  0.642  0.902  0.876  1.0
  O  O48  1  0.382  0.644  0.937  1.0
  O  O49  1  0.967  0.803  0.903  1.0
  O  O50  1  0.835  0.061  0.990  1.0
  O  O51  1  0.201  0.433  0.969  1.0
[/CIF]
.
The compound described by Li2Fe2B2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(7) atom. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and one O(6) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(6), one O(7), and two equivalent O(3) atoms. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted FeO4 tetrahedra that share corners with two equivalent B(1)O4 tetrahedra and corners with two equivalent B(2)O4 tetrahedra. There are two inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form BO4 tetrahedra that share  a cornercorner with one B(2)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. In the second B site, B(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form BO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Li(2), one Fe(1), one B(1), and one B(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(1), and one B(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Fe(2), two equivalent Fe(1), and one B(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(2), and one B(2) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Fe(2), and one B(2) atom to form corner-sharing OLi2FeB tetrahedra. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one B(2) atom. In the seventh O site, O(7) is bonded to one Li(1), one Fe(1), one Fe(2), and one B(1) atom to form distorted corner-sharing OLiFe2B tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Fe2B2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.128
_cell_length_b   5.290
_cell_length_c   9.459
_cell_angle_alpha   56.517
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   506.148
_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  0.341  0.729  0.126  1.0
  Li  Li1  1  0.745  0.014  0.182  1.0
  Li  Li2  1  0.245  0.986  0.318  1.0
  Li  Li3  1  0.841  0.271  0.374  1.0
  Li  Li4  1  0.159  0.729  0.626  1.0
  Li  Li5  1  0.755  0.014  0.682  1.0
  Li  Li6  1  0.255  0.986  0.818  1.0
  Li  Li7  1  0.659  0.271  0.874  1.0
  Fe  Fe8  1  0.095  0.552  0.106  1.0
  Fe  Fe9  1  0.488  0.186  0.197  1.0
  Fe  Fe10  1  0.988  0.814  0.303  1.0
  Fe  Fe11  1  0.595  0.448  0.394  1.0
  Fe  Fe12  1  0.405  0.552  0.606  1.0
  Fe  Fe13  1  0.012  0.186  0.697  1.0
  Fe  Fe14  1  0.512  0.814  0.803  1.0
  Fe  Fe15  1  0.905  0.448  0.894  1.0
  B  B16  1  0.881  0.780  0.029  1.0
  B  B17  1  0.678  0.626  0.042  1.0
  B  B18  1  0.178  0.374  0.458  1.0
  B  B19  1  0.381  0.220  0.471  1.0
  B  B20  1  0.619  0.780  0.529  1.0
  B  B21  1  0.822  0.626  0.542  1.0
  B  B22  1  0.322  0.374  0.958  1.0
  B  B23  1  0.119  0.220  0.971  1.0
  O  O24  1  0.799  0.567  0.031  1.0
  O  O25  1  0.165  0.939  0.010  1.0
  O  O26  1  0.033  0.197  0.097  1.0
  O  O27  1  0.618  0.356  0.063  1.0
  O  O28  1  0.358  0.098  0.124  1.0
  O  O29  1  0.663  0.672  0.180  1.0
  O  O30  1  0.945  0.608  0.195  1.0
  O  O31  1  0.445  0.392  0.305  1.0
  O  O32  1  0.163  0.328  0.320  1.0
  O  O33  1  0.858  0.902  0.376  1.0
  O  O34  1  0.118  0.644  0.437  1.0
  O  O35  1  0.533  0.803  0.403  1.0
  O  O36  1  0.665  0.061  0.490  1.0
  O  O37  1  0.299  0.433  0.469  1.0
  O  O38  1  0.701  0.567  0.531  1.0
  O  O39  1  0.335  0.939  0.510  1.0
  O  O40  1  0.467  0.197  0.597  1.0
  O  O41  1  0.882  0.356  0.563  1.0
  O  O42  1  0.142  0.098  0.624  1.0
  O  O43  1  0.837  0.672  0.680  1.0
  O  O44  1  0.555  0.608  0.695  1.0
  O  O45  1  0.055  0.392  0.805  1.0
  O  O46  1  0.337  0.328  0.820  1.0
  O  O47  1  0.642  0.902  0.876  1.0
  O  O48  1  0.382  0.644  0.937  1.0
  O  O49  1  0.967  0.803  0.903  1.0
  O  O50  1  0.835  0.061  0.990  1.0
  O  O51  1  0.201  0.433  0.969  1.0
[/CIF]
.