The material structure described by Li2FeP2O7 crystallizes in the triclinic P1 space group. There are eight inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(15), one O(18), one O(21), and one O(9) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(7)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the second Li site, Li(2) is bonded to one O(10), one O(16), one O(17), and one O(22) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(8)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, and  an edgeedge with one Li(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the third Li site, Li(3) is bonded to one O(11), one O(14), one O(19), and one O(24) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(5)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Li(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the fourth Li site, Li(4) is bonded to one O(12), one O(13), one O(20), and one O(23) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(6)O4 tetrahedra,  an edgeedge with one Fe(4)O6 octahedra, and  an edgeedge with one Li(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 74-80°. In the fifth Li site, Li(5) is bonded to one O(13), one O(20), one O(26), and one O(5) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Li(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the sixth Li site, Li(6) is bonded to one O(14), one O(19), one O(25), and one O(6) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Fe(4)O6 octahedra, and  an edgeedge with one Li(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the seventh Li site, Li(7) is bonded to one O(16), one O(17), one O(27), and one O(7) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the eighth Li site, Li(8) is bonded to one O(15), one O(18), one O(28), and one O(8) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(15), one O(18), one O(22), one O(27), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(8)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Li(8)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(11), one O(14), one O(20), one O(23), one O(25), and one O(5) atom to form FeO6 octahedra that share  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Li(6)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent P(5)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra, and  an edgeedge with one Li(5)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to one O(10), one O(16), one O(17), one O(21), one O(28), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(7)O4 tetrahedra,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Li(7)O4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one O(12), one O(13), one O(19), one O(24), one O(26), and one O(6) atom to form FeO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(5)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, corners with two equivalent P(6)O4 tetrahedra,  an edgeedge with one Li(4)O4 tetrahedra, and  an edgeedge with one Li(6)O4 tetrahedra. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(15), one O(27), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent Li(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-56°. In the second P site, P(2) is bonded to one O(16), one O(2), one O(28), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent Li(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-56°. In the third P site, P(3) is bonded to one O(1), one O(13), one O(25), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent Li(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-55°. In the fourth P site, P(4) is bonded to one O(14), one O(2), one O(26), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Li(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-56°. In the fifth P site, P(5) is bonded to one O(11), one O(19), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and corners with two equivalent Li(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-56°. In the sixth P site, P(6) is bonded to one O(12), one O(20), one O(24), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and corners with two equivalent Li(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-55°. In the seventh P site, P(7) is bonded to one O(17), one O(21), one O(3), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, and corners with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-56°. In the eighth P site, P(8) is bonded to one O(10), one O(18), one O(22), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and corners with two equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-56°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one P(2) and one P(4) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one P(5) and one P(7) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one P(6) and one P(8) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(5), one Fe(2), and one P(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(6), one Fe(4), and one P(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(7), one Fe(3), and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(8), one Fe(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(7) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(3), and one P(8) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(3), one Fe(2), and one P(5) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Li(4), one Fe(4), and one P(6) atom. In the thirteenth O site, O(13) is bonded to one Li(4), one Li(5), one Fe(4), and one P(3) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the fourteenth O site, O(14) is bonded to one Li(3), one Li(6), one Fe(2), and one P(4) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the fifteenth O site, O(15) is bonded to one Li(1), one Li(8), one Fe(1), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the sixteenth O site, O(16) is bonded to one Li(2), one Li(7), one Fe(3), and one P(2) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the seventeenth O site, O(17) is bonded to one Li(2), one Li(7), one Fe(3), and one P(7) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the eighteenth O site, O(18) is bonded to one Li(1), one Li(8), one Fe(1), and one P(8) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the nineteenth O site, O(19) is bonded to one Li(3), one Li(6), one Fe(4), and one P(5) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the twentieth O site, O(20) is bonded to one Li(4), one Li(5), one Fe(2), and one P(6) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the twenty-first O site, O(21) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(3), and one P(7) atom. In the twenty-second O site, O(22) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Li(4), one Fe(2), and one P(5) atom. In the twenty-fourth O site, O(24) is bonded in a distorted trigonal planar geometry to one Li(3), one Fe(4), and one P(6) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Li(6), one Fe(2), and one P(3) atom. In the twenty-sixth O site, O(26) is bonded in a distorted trigonal planar geometry to one Li(5), one Fe(4), and one P(4) atom. In the twenty-seventh O site, O(27) is bonded in a distorted trigonal planar geometry to one Li(7), one Fe(1), and one P(1) atom. In the twenty-eighth O site, O(28) is bonded in a distorted trigonal planar geometry to one Li(8), one Fe(3), and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2FeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.064
_cell_length_b   5.139
_cell_length_c   13.227
_cell_angle_alpha   79.572
_cell_angle_beta   89.960
_cell_angle_gamma   60.487
_symmetry_Int_Tables_number   1
_cell_volume   293.000
_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
  Fe  Fe0  1  0.500  0.000  0.500  1.0
  Fe  Fe1  1  1.000  1.000  1.000  1.0
  Li  Li2  1  0.206  0.720  0.410  1.0
  Li  Li3  1  0.425  0.280  0.090  1.0
  Li  Li4  1  0.576  0.719  0.910  1.0
  Li  Li5  1  0.794  0.281  0.590  1.0
  O  O6  1  0.298  0.500  0.750  1.0
  O  O7  1  0.702  0.500  0.250  1.0
  O  O8  1  0.207  0.131  0.882  1.0
  O  O9  1  0.836  0.869  0.619  1.0
  O  O10  1  0.163  0.132  0.381  1.0
  O  O11  1  0.794  0.869  0.118  1.0
  O  O12  1  0.543  0.342  0.927  1.0
  O  O13  1  0.383  0.659  0.572  1.0
  O  O14  1  0.617  0.342  0.428  1.0
  O  O15  1  0.457  0.658  0.073  1.0
  O  O16  1  0.840  0.692  0.397  1.0
  O  O17  1  0.031  0.308  0.104  1.0
  O  O18  1  0.969  0.691  0.897  1.0
  O  O19  1  0.160  0.309  0.603  1.0
  P  P20  1  0.158  0.586  0.631  1.0
  P  P21  1  0.245  0.414  0.869  1.0
  P  P22  1  0.755  0.586  0.131  1.0
  P  P23  1  0.842  0.414  0.369  1.0
[/CIF]
.
The material structure described by Li2FeP2O7 crystallizes in the triclinic P1 space group. There are eight inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(15), one O(18), one O(21), and one O(9) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(7)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the second Li site, Li(2) is bonded to one O(10), one O(16), one O(17), and one O(22) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(8)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, and  an edgeedge with one Li(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the third Li site, Li(3) is bonded to one O(11), one O(14), one O(19), and one O(24) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(5)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Li(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the fourth Li site, Li(4) is bonded to one O(12), one O(13), one O(20), and one O(23) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(6)O4 tetrahedra,  an edgeedge with one Fe(4)O6 octahedra, and  an edgeedge with one Li(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 74-80°. In the fifth Li site, Li(5) is bonded to one O(13), one O(20), one O(26), and one O(5) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Li(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the sixth Li site, Li(6) is bonded to one O(14), one O(19), one O(25), and one O(6) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Fe(4)O6 octahedra, and  an edgeedge with one Li(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the seventh Li site, Li(7) is bonded to one O(16), one O(17), one O(27), and one O(7) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. In the eighth Li site, Li(8) is bonded to one O(15), one O(18), one O(28), and one O(8) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 73-80°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(15), one O(18), one O(22), one O(27), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(8)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Li(8)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(11), one O(14), one O(20), one O(23), one O(25), and one O(5) atom to form FeO6 octahedra that share  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Li(6)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent P(5)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra, and  an edgeedge with one Li(5)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to one O(10), one O(16), one O(17), one O(21), one O(28), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(7)O4 tetrahedra,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Li(7)O4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one O(12), one O(13), one O(19), one O(24), one O(26), and one O(6) atom to form FeO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(5)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, corners with two equivalent P(6)O4 tetrahedra,  an edgeedge with one Li(4)O4 tetrahedra, and  an edgeedge with one Li(6)O4 tetrahedra. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(15), one O(27), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent Li(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-56°. In the second P site, P(2) is bonded to one O(16), one O(2), one O(28), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent Li(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-56°. In the third P site, P(3) is bonded to one O(1), one O(13), one O(25), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent Li(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-55°. In the fourth P site, P(4) is bonded to one O(14), one O(2), one O(26), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Li(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-56°. In the fifth P site, P(5) is bonded to one O(11), one O(19), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and corners with two equivalent Li(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-56°. In the sixth P site, P(6) is bonded to one O(12), one O(20), one O(24), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and corners with two equivalent Li(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-55°. In the seventh P site, P(7) is bonded to one O(17), one O(21), one O(3), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, and corners with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-56°. In the eighth P site, P(8) is bonded to one O(10), one O(18), one O(22), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(8)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and corners with two equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-56°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one P(2) and one P(4) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one P(5) and one P(7) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one P(6) and one P(8) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(5), one Fe(2), and one P(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(6), one Fe(4), and one P(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(7), one Fe(3), and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(8), one Fe(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(7) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(3), and one P(8) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(3), one Fe(2), and one P(5) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Li(4), one Fe(4), and one P(6) atom. In the thirteenth O site, O(13) is bonded to one Li(4), one Li(5), one Fe(4), and one P(3) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the fourteenth O site, O(14) is bonded to one Li(3), one Li(6), one Fe(2), and one P(4) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the fifteenth O site, O(15) is bonded to one Li(1), one Li(8), one Fe(1), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the sixteenth O site, O(16) is bonded to one Li(2), one Li(7), one Fe(3), and one P(2) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the seventeenth O site, O(17) is bonded to one Li(2), one Li(7), one Fe(3), and one P(7) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the eighteenth O site, O(18) is bonded to one Li(1), one Li(8), one Fe(1), and one P(8) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the nineteenth O site, O(19) is bonded to one Li(3), one Li(6), one Fe(4), and one P(5) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the twentieth O site, O(20) is bonded to one Li(4), one Li(5), one Fe(2), and one P(6) atom to form a mixture of distorted corner and edge-sharing OLi2FeP tetrahedra. In the twenty-first O site, O(21) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(3), and one P(7) atom. In the twenty-second O site, O(22) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Li(4), one Fe(2), and one P(5) atom. In the twenty-fourth O site, O(24) is bonded in a distorted trigonal planar geometry to one Li(3), one Fe(4), and one P(6) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Li(6), one Fe(2), and one P(3) atom. In the twenty-sixth O site, O(26) is bonded in a distorted trigonal planar geometry to one Li(5), one Fe(4), and one P(4) atom. In the twenty-seventh O site, O(27) is bonded in a distorted trigonal planar geometry to one Li(7), one Fe(1), and one P(1) atom. In the twenty-eighth O site, O(28) is bonded in a distorted trigonal planar geometry to one Li(8), one Fe(3), and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2FeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.064
_cell_length_b   5.139
_cell_length_c   13.227
_cell_angle_alpha   79.572
_cell_angle_beta   89.960
_cell_angle_gamma   60.487
_symmetry_Int_Tables_number   1
_cell_volume   293.000
_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
  Fe  Fe0  1  0.500  0.000  0.500  1.0
  Fe  Fe1  1  1.000  1.000  1.000  1.0
  Li  Li2  1  0.206  0.720  0.410  1.0
  Li  Li3  1  0.425  0.280  0.090  1.0
  Li  Li4  1  0.576  0.719  0.910  1.0
  Li  Li5  1  0.794  0.281  0.590  1.0
  O  O6  1  0.298  0.500  0.750  1.0
  O  O7  1  0.702  0.500  0.250  1.0
  O  O8  1  0.207  0.131  0.882  1.0
  O  O9  1  0.836  0.869  0.619  1.0
  O  O10  1  0.163  0.132  0.381  1.0
  O  O11  1  0.794  0.869  0.118  1.0
  O  O12  1  0.543  0.342  0.927  1.0
  O  O13  1  0.383  0.659  0.572  1.0
  O  O14  1  0.617  0.342  0.428  1.0
  O  O15  1  0.457  0.658  0.073  1.0
  O  O16  1  0.840  0.692  0.397  1.0
  O  O17  1  0.031  0.308  0.104  1.0
  O  O18  1  0.969  0.691  0.897  1.0
  O  O19  1  0.160  0.309  0.603  1.0
  P  P20  1  0.158  0.586  0.631  1.0
  P  P21  1  0.245  0.414  0.869  1.0
  P  P22  1  0.755  0.586  0.131  1.0
  P  P23  1  0.842  0.414  0.369  1.0
[/CIF]
.