The compound described by LiFeP2O7 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(12), one O(3), one O(4), and one O(7) atom to form distorted LiO4 trigonal pyramids that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-71°. In the second Li site, Li(2) is bonded to one O(10), one O(11), one O(5), and one O(6) atom to form LiO4 trigonal pyramids that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-72°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(12), one O(3), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and corners with two equivalent Li(2)O4 trigonal pyramids. In the second Fe site, Fe(2) is bonded to one O(11), one O(14), one O(2), one O(4), one O(5), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, corners with two equivalent Li(2)O4 trigonal pyramids, and  an edgeedge with one Li(1)O4 trigonal pyramid. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid, and corners with two equivalent Li(2)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 42-51°. In the second P site, P(2) is bonded to one O(13), one O(14), one O(2), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-41°. In the third P site, P(3) is bonded to one O(1), one O(10), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid, and  a cornercorner with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 21-55°. In the fourth P site, P(4) is bonded to one O(11), one O(12), one O(13), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and corners with two equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 28-54°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 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 Fe(2) and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(1), one Fe(2), and one P(4) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(2), and one P(3) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Li(2), one Fe(1), and one P(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one P(4) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(1), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one P(2) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. is represented by the CIF file [CIF]
data_LiFeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.089
_cell_length_b   6.792
_cell_length_c   8.298
_cell_angle_alpha   68.607
_cell_angle_beta   87.241
_cell_angle_gamma   87.353
_symmetry_Int_Tables_number   1
_cell_volume   266.628
_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  0.280  0.822  0.997  1.0
  Li  Li1  1  0.790  0.179  0.440  1.0
  Fe  Fe2  1  0.757  0.793  0.270  1.0
  Fe  Fe3  1  0.241  0.227  0.728  1.0
  P  P4  1  0.282  0.456  0.307  1.0
  P  P5  1  0.718  0.546  0.688  1.0
  P  P6  1  0.237  0.113  0.172  1.0
  P  P7  1  0.766  0.891  0.830  1.0
  O  O8  1  0.288  0.352  0.159  1.0
  O  O9  1  0.904  0.355  0.762  1.0
  O  O10  1  0.115  0.660  0.222  1.0
  O  O11  1  0.060  0.933  0.789  1.0
  O  O12  1  0.153  0.298  0.471  1.0
  O  O13  1  0.570  0.497  0.327  1.0
  O  O14  1  0.268  0.119  0.988  1.0
  O  O15  1  0.815  0.709  0.517  1.0
  O  O16  1  0.442  0.967  0.291  1.0
  O  O17  1  0.955  0.064  0.248  1.0
  O  O18  1  0.588  0.054  0.696  1.0
  O  O19  1  0.680  0.857  0.018  1.0
  O  O20  1  0.711  0.660  0.828  1.0
  O  O21  1  0.436  0.481  0.686  1.0
[/CIF]
.
The compound described by LiFeP2O7 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(12), one O(3), one O(4), and one O(7) atom to form distorted LiO4 trigonal pyramids that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-71°. In the second Li site, Li(2) is bonded to one O(10), one O(11), one O(5), and one O(6) atom to form LiO4 trigonal pyramids that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-72°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(12), one O(3), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and corners with two equivalent Li(2)O4 trigonal pyramids. In the second Fe site, Fe(2) is bonded to one O(11), one O(14), one O(2), one O(4), one O(5), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, corners with two equivalent Li(2)O4 trigonal pyramids, and  an edgeedge with one Li(1)O4 trigonal pyramid. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid, and corners with two equivalent Li(2)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 42-51°. In the second P site, P(2) is bonded to one O(13), one O(14), one O(2), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-41°. In the third P site, P(3) is bonded to one O(1), one O(10), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid, and  a cornercorner with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 21-55°. In the fourth P site, P(4) is bonded to one O(11), one O(12), one O(13), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and corners with two equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 28-54°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 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 Fe(2) and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(1), one Fe(2), and one P(4) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(2), and one P(3) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Li(2), one Fe(1), and one P(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one P(4) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(1), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one P(2) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. is represented by the CIF file [CIF]
data_LiFeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.089
_cell_length_b   6.792
_cell_length_c   8.298
_cell_angle_alpha   68.607
_cell_angle_beta   87.241
_cell_angle_gamma   87.353
_symmetry_Int_Tables_number   1
_cell_volume   266.628
_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  0.280  0.822  0.997  1.0
  Li  Li1  1  0.790  0.179  0.440  1.0
  Fe  Fe2  1  0.757  0.793  0.270  1.0
  Fe  Fe3  1  0.241  0.227  0.728  1.0
  P  P4  1  0.282  0.456  0.307  1.0
  P  P5  1  0.718  0.546  0.688  1.0
  P  P6  1  0.237  0.113  0.172  1.0
  P  P7  1  0.766  0.891  0.830  1.0
  O  O8  1  0.288  0.352  0.159  1.0
  O  O9  1  0.904  0.355  0.762  1.0
  O  O10  1  0.115  0.660  0.222  1.0
  O  O11  1  0.060  0.933  0.789  1.0
  O  O12  1  0.153  0.298  0.471  1.0
  O  O13  1  0.570  0.497  0.327  1.0
  O  O14  1  0.268  0.119  0.988  1.0
  O  O15  1  0.815  0.709  0.517  1.0
  O  O16  1  0.442  0.967  0.291  1.0
  O  O17  1  0.955  0.064  0.248  1.0
  O  O18  1  0.588  0.054  0.696  1.0
  O  O19  1  0.680  0.857  0.018  1.0
  O  O20  1  0.711  0.660  0.828  1.0
  O  O21  1  0.436  0.481  0.686  1.0
[/CIF]
.