The structure described by FeP2O7 crystallizes in the monoclinic C2/m space group. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 25-50°. In the second P site, P(2) is bonded to one O(4), one O(5), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to one P(2) atom. is represented by the CIF card [CIF]
data_FeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.567
_cell_length_b   6.567
_cell_length_c   6.984
_cell_angle_alpha   68.201
_cell_angle_beta   68.201
_cell_angle_gamma   79.941
_symmetry_Int_Tables_number   1
_cell_volume   259.404
_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  0.306  0.694  0.500  1.0
  Fe  Fe1  1  0.694  0.306  0.500  1.0
  P  P2  1  0.234  0.234  0.425  1.0
  P  P3  1  0.690  0.690  0.051  1.0
  P  P4  1  0.766  0.766  0.575  1.0
  P  P5  1  0.310  0.310  0.949  1.0
  O  O6  1  0.462  0.769  0.175  1.0
  O  O7  1  0.769  0.462  0.175  1.0
  O  O8  1  0.638  0.638  0.510  1.0
  O  O9  1  0.990  0.291  0.500  1.0
  O  O10  1  0.291  0.990  0.500  1.0
  O  O11  1  0.669  0.669  0.839  1.0
  O  O12  1  0.141  0.141  0.014  1.0
  O  O13  1  0.709  0.010  0.500  1.0
  O  O14  1  0.010  0.709  0.500  1.0
  O  O15  1  0.362  0.362  0.490  1.0
  O  O16  1  0.231  0.538  0.825  1.0
  O  O17  1  0.538  0.231  0.825  1.0
  O  O18  1  0.859  0.859  0.986  1.0
  O  O19  1  0.331  0.331  0.161  1.0
[/CIF]
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The structure described by FeP2O7 crystallizes in the monoclinic C2/m space group. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 25-50°. In the second P site, P(2) is bonded to one O(4), one O(5), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to one P(2) atom. is represented by the CIF card [CIF]
data_FeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.567
_cell_length_b   6.567
_cell_length_c   6.984
_cell_angle_alpha   68.201
_cell_angle_beta   68.201
_cell_angle_gamma   79.941
_symmetry_Int_Tables_number   1
_cell_volume   259.404
_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  0.306  0.694  0.500  1.0
  Fe  Fe1  1  0.694  0.306  0.500  1.0
  P  P2  1  0.234  0.234  0.425  1.0
  P  P3  1  0.690  0.690  0.051  1.0
  P  P4  1  0.766  0.766  0.575  1.0
  P  P5  1  0.310  0.310  0.949  1.0
  O  O6  1  0.462  0.769  0.175  1.0
  O  O7  1  0.769  0.462  0.175  1.0
  O  O8  1  0.638  0.638  0.510  1.0
  O  O9  1  0.990  0.291  0.500  1.0
  O  O10  1  0.291  0.990  0.500  1.0
  O  O11  1  0.669  0.669  0.839  1.0
  O  O12  1  0.141  0.141  0.014  1.0
  O  O13  1  0.709  0.010  0.500  1.0
  O  O14  1  0.010  0.709  0.500  1.0
  O  O15  1  0.362  0.362  0.490  1.0
  O  O16  1  0.231  0.538  0.825  1.0
  O  O17  1  0.538  0.231  0.825  1.0
  O  O18  1  0.859  0.859  0.986  1.0
  O  O19  1  0.331  0.331  0.161  1.0
[/CIF]
.