The material structure described by Li2FeP2O7 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 trigonal non-coplanar geometry to one O(2), one O(3), and one O(6) atom. In the second Li site, Li(2) is bonded to one O(1), one O(4), and two equivalent O(7) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-78°. Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form FeO6 octahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-57°. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-55°. There are seven inequivalent O sites. In the first O site, O(7) is bonded to two equivalent Li(2), one Fe(1), and one P(2) atom to form distorted edge-sharing OLi2FeP trigonal pyramids. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(1) atom. In the third O site, O(2) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. In the fourth O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Li(2), one Fe(1), and one P(2) atom. In the sixth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. is represented by the CIF card [CIF]
data_Li2FeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.071
_cell_length_b   8.503
_cell_length_c   14.039
_cell_angle_alpha   65.593
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   551.335
_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  0.242  0.045  0.826  1.0
  Li  Li1  1  0.221  0.506  0.576  1.0
  Li  Li2  1  0.258  0.045  0.326  1.0
  Li  Li3  1  0.742  0.955  0.674  1.0
  Li  Li4  1  0.779  0.494  0.424  1.0
  Li  Li5  1  0.758  0.955  0.174  1.0
  Li  Li6  1  0.721  0.494  0.924  1.0
  Li  Li7  1  0.279  0.506  0.076  1.0
  Fe  Fe8  1  0.256  0.221  0.521  1.0
  Fe  Fe9  1  0.244  0.221  0.021  1.0
  Fe  Fe10  1  0.756  0.779  0.979  1.0
  Fe  Fe11  1  0.744  0.779  0.479  1.0
  P  P12  1  0.238  0.808  0.623  1.0
  P  P13  1  0.762  0.192  0.377  1.0
  P  P14  1  0.738  0.192  0.877  1.0
  P  P15  1  0.262  0.808  0.123  1.0
  P  P16  1  0.265  0.671  0.353  1.0
  P  P17  1  0.765  0.329  0.147  1.0
  P  P18  1  0.235  0.671  0.853  1.0
  P  P19  1  0.735  0.329  0.647  1.0
  O  O20  1  0.872  0.274  0.942  1.0
  O  O21  1  0.442  0.166  0.899  1.0
  O  O22  1  0.942  0.834  0.601  1.0
  O  O23  1  0.558  0.834  0.101  1.0
  O  O24  1  0.592  0.184  0.142  1.0
  O  O25  1  0.939  0.699  0.862  1.0
  O  O26  1  0.717  0.339  0.259  1.0
  O  O27  1  0.875  0.029  0.880  1.0
  O  O28  1  0.561  0.699  0.362  1.0
  O  O29  1  0.283  0.661  0.741  1.0
  O  O30  1  0.372  0.726  0.558  1.0
  O  O31  1  0.375  0.971  0.620  1.0
  O  O32  1  0.783  0.339  0.759  1.0
  O  O33  1  0.058  0.166  0.399  1.0
  O  O34  1  0.128  0.726  0.058  1.0
  O  O35  1  0.829  0.508  0.568  1.0
  O  O36  1  0.671  0.508  0.068  1.0
  O  O37  1  0.329  0.492  0.932  1.0
  O  O38  1  0.217  0.661  0.241  1.0
  O  O39  1  0.908  0.184  0.642  1.0
  O  O40  1  0.171  0.492  0.432  1.0
  O  O41  1  0.125  0.971  0.120  1.0
  O  O42  1  0.625  0.029  0.380  1.0
  O  O43  1  0.092  0.816  0.358  1.0
  O  O44  1  0.408  0.816  0.858  1.0
  O  O45  1  0.439  0.301  0.638  1.0
  O  O46  1  0.628  0.274  0.442  1.0
  O  O47  1  0.061  0.301  0.138  1.0
[/CIF]
.
The material structure described by Li2FeP2O7 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 trigonal non-coplanar geometry to one O(2), one O(3), and one O(6) atom. In the second Li site, Li(2) is bonded to one O(1), one O(4), and two equivalent O(7) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-78°. Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form FeO6 octahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-57°. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-55°. There are seven inequivalent O sites. In the first O site, O(7) is bonded to two equivalent Li(2), one Fe(1), and one P(2) atom to form distorted edge-sharing OLi2FeP trigonal pyramids. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(1) atom. In the third O site, O(2) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. In the fourth O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Li(2), one Fe(1), and one P(2) atom. In the sixth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. is represented by the CIF card [CIF]
data_Li2FeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.071
_cell_length_b   8.503
_cell_length_c   14.039
_cell_angle_alpha   65.593
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   551.335
_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  0.242  0.045  0.826  1.0
  Li  Li1  1  0.221  0.506  0.576  1.0
  Li  Li2  1  0.258  0.045  0.326  1.0
  Li  Li3  1  0.742  0.955  0.674  1.0
  Li  Li4  1  0.779  0.494  0.424  1.0
  Li  Li5  1  0.758  0.955  0.174  1.0
  Li  Li6  1  0.721  0.494  0.924  1.0
  Li  Li7  1  0.279  0.506  0.076  1.0
  Fe  Fe8  1  0.256  0.221  0.521  1.0
  Fe  Fe9  1  0.244  0.221  0.021  1.0
  Fe  Fe10  1  0.756  0.779  0.979  1.0
  Fe  Fe11  1  0.744  0.779  0.479  1.0
  P  P12  1  0.238  0.808  0.623  1.0
  P  P13  1  0.762  0.192  0.377  1.0
  P  P14  1  0.738  0.192  0.877  1.0
  P  P15  1  0.262  0.808  0.123  1.0
  P  P16  1  0.265  0.671  0.353  1.0
  P  P17  1  0.765  0.329  0.147  1.0
  P  P18  1  0.235  0.671  0.853  1.0
  P  P19  1  0.735  0.329  0.647  1.0
  O  O20  1  0.872  0.274  0.942  1.0
  O  O21  1  0.442  0.166  0.899  1.0
  O  O22  1  0.942  0.834  0.601  1.0
  O  O23  1  0.558  0.834  0.101  1.0
  O  O24  1  0.592  0.184  0.142  1.0
  O  O25  1  0.939  0.699  0.862  1.0
  O  O26  1  0.717  0.339  0.259  1.0
  O  O27  1  0.875  0.029  0.880  1.0
  O  O28  1  0.561  0.699  0.362  1.0
  O  O29  1  0.283  0.661  0.741  1.0
  O  O30  1  0.372  0.726  0.558  1.0
  O  O31  1  0.375  0.971  0.620  1.0
  O  O32  1  0.783  0.339  0.759  1.0
  O  O33  1  0.058  0.166  0.399  1.0
  O  O34  1  0.128  0.726  0.058  1.0
  O  O35  1  0.829  0.508  0.568  1.0
  O  O36  1  0.671  0.508  0.068  1.0
  O  O37  1  0.329  0.492  0.932  1.0
  O  O38  1  0.217  0.661  0.241  1.0
  O  O39  1  0.908  0.184  0.642  1.0
  O  O40  1  0.171  0.492  0.432  1.0
  O  O41  1  0.125  0.971  0.120  1.0
  O  O42  1  0.625  0.029  0.380  1.0
  O  O43  1  0.092  0.816  0.358  1.0
  O  O44  1  0.408  0.816  0.858  1.0
  O  O45  1  0.439  0.301  0.638  1.0
  O  O46  1  0.628  0.274  0.442  1.0
  O  O47  1  0.061  0.301  0.138  1.0
[/CIF]
.