The compound described by Fe7(PO4)8 crystallizes in the monoclinic Cm space group. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(19), one O(2), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with four equivalent Fe(3)O6 pentagonal pyramids,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(5), one O(8), two equivalent O(12), and two equivalent O(20) atoms to form distorted FeO6 pentagonal pyramids that share corners with four equivalent Fe(5)O6 pentagonal pyramids,  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 P(6)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to one O(1), one O(10), one O(11), one O(15), one O(3), and one O(4) atom to form distorted FeO6 pentagonal pyramids that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the fourth Fe site, Fe(4) is bonded to one O(14), one O(17), two equivalent O(18), and two equivalent O(9) atoms to form distorted FeO6 pentagonal pyramids that share corners with four equivalent Fe(5)O6 pentagonal pyramids,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. In the fifth Fe site, Fe(5) is bonded to one O(12), one O(16), one O(18), one O(20), one O(6), and one O(9) atom to form distorted FeO6 pentagonal pyramids that share corners with two equivalent Fe(2)O6 pentagonal pyramids, corners with two equivalent Fe(4)O6 pentagonal pyramids,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  an edgeedge with one P(4)O4 tetrahedra. There are six inequivalent P sites. In the first P site, P(1) is bonded to one O(5), one O(7), and two equivalent O(1) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 pentagonal pyramid, corners with two equivalent Fe(3)O6 pentagonal pyramids, and  an edgeedge with one Fe(1)O6 octahedra. In the second P site, P(2) is bonded to one O(10), one O(16), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 pentagonal pyramid,  a cornercorner with one Fe(5)O6 pentagonal pyramid, and  an edgeedge with one Fe(3)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 53°. In the third P site, P(3) is bonded to one O(2), one O(8), and two equivalent O(9) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 pentagonal pyramid, corners with two equivalent Fe(5)O6 pentagonal pyramids, and  an edgeedge with one Fe(4)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 37°. In the fourth P site, P(4) is bonded to one O(12), one O(15), one O(18), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 pentagonal pyramid,  a cornercorner with one Fe(3)O6 pentagonal pyramid,  a cornercorner with one Fe(4)O6 pentagonal pyramid,  a cornercorner with one Fe(5)O6 pentagonal pyramid, and  an edgeedge with one Fe(5)O6 pentagonal pyramid. In the fifth P site, P(5) is bonded to one O(14), one O(19), and two equivalent O(11) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 pentagonal pyramid, and corners with two equivalent Fe(3)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 50°. In the sixth P site, P(6) is bonded to one O(13), one O(17), and two equivalent O(20) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 pentagonal pyramid, corners with two equivalent Fe(5)O6 pentagonal pyramids, and  an edgeedge with one Fe(2)O6 pentagonal pyramid. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the third O site, O(3) is bonded in a water-like geometry to one Fe(3) and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Fe(5) and one P(4) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one P(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one Fe(3) and one P(5) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(5), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a single-bond geometry to one P(6) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Fe(4) and one P(5) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(4) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Fe(5) and one P(2) atom. In the seventeenth O site, O(17) is bonded in a distorted bent 150 degrees geometry to one Fe(4) and one P(6) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one P(4) atom. In the nineteenth O site, O(19) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(5) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(5), and one P(6) atom. is represented by the CIF card [CIF]
data_Fe7(PO4)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.773
_cell_length_b   7.773
_cell_length_c   11.178
_cell_angle_alpha   74.025
_cell_angle_beta   74.025
_cell_angle_gamma   101.499
_symmetry_Int_Tables_number   1
_cell_volume   595.909
_cell_formula_units_Z   1
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  0.520  0.520  0.224  1.0
  Fe  Fe1  1  0.001  0.001  0.726  1.0
  Fe  Fe2  1  0.501  0.990  0.274  1.0
  Fe  Fe3  1  0.505  0.505  0.723  1.0
  Fe  Fe4  1  0.979  0.481  0.775  1.0
  Fe  Fe5  1  0.990  0.501  0.274  1.0
  Fe  Fe6  1  0.481  0.979  0.775  1.0
  P  P7  1  0.213  0.213  0.399  1.0
  P  P8  1  0.858  0.362  0.103  1.0
  P  P9  1  0.641  0.641  0.898  1.0
  P  P10  1  0.292  0.791  0.601  1.0
  P  P11  1  0.702  0.702  0.399  1.0
  P  P12  1  0.362  0.858  0.103  1.0
  P  P13  1  0.145  0.145  0.894  1.0
  P  P14  1  0.791  0.292  0.601  1.0
  O  O15  1  0.218  0.417  0.325  1.0
  O  O16  1  0.531  0.531  0.044  1.0
  O  O17  1  0.993  0.319  0.180  1.0
  O  O18  1  0.785  0.501  0.171  1.0
  O  O19  1  0.173  0.173  0.549  1.0
  O  O20  1  0.437  0.935  0.622  1.0
  O  O21  1  0.417  0.218  0.325  1.0
  O  O22  1  0.053  0.053  0.406  1.0
  O  O23  1  0.806  0.806  0.877  1.0
  O  O24  1  0.510  0.708  0.821  1.0
  O  O25  1  0.698  0.193  0.126  1.0
  O  O26  1  0.699  0.902  0.329  1.0
  O  O27  1  0.084  0.783  0.677  1.0
  O  O28  1  0.042  0.042  0.043  1.0
  O  O29  1  0.319  0.993  0.180  1.0
  O  O30  1  0.666  0.666  0.548  1.0
  O  O31  1  0.326  0.829  0.454  1.0
  O  O32  1  0.708  0.510  0.821  1.0
  O  O33  1  0.964  0.464  0.953  1.0
  O  O34  1  0.902  0.699  0.329  1.0
  O  O35  1  0.309  0.309  0.875  1.0
  O  O36  1  0.280  0.583  0.677  1.0
  O  O37  1  0.501  0.785  0.171  1.0
  O  O38  1  0.193  0.698  0.126  1.0
  O  O39  1  0.935  0.437  0.622  1.0
  O  O40  1  0.583  0.280  0.677  1.0
  O  O41  1  0.553  0.553  0.384  1.0
  O  O42  1  0.012  0.210  0.818  1.0
  O  O43  1  0.829  0.326  0.454  1.0
  O  O44  1  0.210  0.012  0.818  1.0
  O  O45  1  0.464  0.964  0.953  1.0
  O  O46  1  0.783  0.084  0.677  1.0
[/CIF]
.
The compound described by Fe7(PO4)8 crystallizes in the monoclinic Cm space group. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(19), one O(2), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with four equivalent Fe(3)O6 pentagonal pyramids,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(5), one O(8), two equivalent O(12), and two equivalent O(20) atoms to form distorted FeO6 pentagonal pyramids that share corners with four equivalent Fe(5)O6 pentagonal pyramids,  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 P(6)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to one O(1), one O(10), one O(11), one O(15), one O(3), and one O(4) atom to form distorted FeO6 pentagonal pyramids that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the fourth Fe site, Fe(4) is bonded to one O(14), one O(17), two equivalent O(18), and two equivalent O(9) atoms to form distorted FeO6 pentagonal pyramids that share corners with four equivalent Fe(5)O6 pentagonal pyramids,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. In the fifth Fe site, Fe(5) is bonded to one O(12), one O(16), one O(18), one O(20), one O(6), and one O(9) atom to form distorted FeO6 pentagonal pyramids that share corners with two equivalent Fe(2)O6 pentagonal pyramids, corners with two equivalent Fe(4)O6 pentagonal pyramids,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  an edgeedge with one P(4)O4 tetrahedra. There are six inequivalent P sites. In the first P site, P(1) is bonded to one O(5), one O(7), and two equivalent O(1) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 pentagonal pyramid, corners with two equivalent Fe(3)O6 pentagonal pyramids, and  an edgeedge with one Fe(1)O6 octahedra. In the second P site, P(2) is bonded to one O(10), one O(16), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 pentagonal pyramid,  a cornercorner with one Fe(5)O6 pentagonal pyramid, and  an edgeedge with one Fe(3)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 53°. In the third P site, P(3) is bonded to one O(2), one O(8), and two equivalent O(9) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 pentagonal pyramid, corners with two equivalent Fe(5)O6 pentagonal pyramids, and  an edgeedge with one Fe(4)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 37°. In the fourth P site, P(4) is bonded to one O(12), one O(15), one O(18), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 pentagonal pyramid,  a cornercorner with one Fe(3)O6 pentagonal pyramid,  a cornercorner with one Fe(4)O6 pentagonal pyramid,  a cornercorner with one Fe(5)O6 pentagonal pyramid, and  an edgeedge with one Fe(5)O6 pentagonal pyramid. In the fifth P site, P(5) is bonded to one O(14), one O(19), and two equivalent O(11) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 pentagonal pyramid, and corners with two equivalent Fe(3)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 50°. In the sixth P site, P(6) is bonded to one O(13), one O(17), and two equivalent O(20) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 pentagonal pyramid, corners with two equivalent Fe(5)O6 pentagonal pyramids, and  an edgeedge with one Fe(2)O6 pentagonal pyramid. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the third O site, O(3) is bonded in a water-like geometry to one Fe(3) and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Fe(5) and one P(4) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one P(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one Fe(3) and one P(5) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(5), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a single-bond geometry to one P(6) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Fe(4) and one P(5) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(4) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Fe(5) and one P(2) atom. In the seventeenth O site, O(17) is bonded in a distorted bent 150 degrees geometry to one Fe(4) and one P(6) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one P(4) atom. In the nineteenth O site, O(19) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(5) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(5), and one P(6) atom. is represented by the CIF card [CIF]
data_Fe7(PO4)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.773
_cell_length_b   7.773
_cell_length_c   11.178
_cell_angle_alpha   74.025
_cell_angle_beta   74.025
_cell_angle_gamma   101.499
_symmetry_Int_Tables_number   1
_cell_volume   595.909
_cell_formula_units_Z   1
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  0.520  0.520  0.224  1.0
  Fe  Fe1  1  0.001  0.001  0.726  1.0
  Fe  Fe2  1  0.501  0.990  0.274  1.0
  Fe  Fe3  1  0.505  0.505  0.723  1.0
  Fe  Fe4  1  0.979  0.481  0.775  1.0
  Fe  Fe5  1  0.990  0.501  0.274  1.0
  Fe  Fe6  1  0.481  0.979  0.775  1.0
  P  P7  1  0.213  0.213  0.399  1.0
  P  P8  1  0.858  0.362  0.103  1.0
  P  P9  1  0.641  0.641  0.898  1.0
  P  P10  1  0.292  0.791  0.601  1.0
  P  P11  1  0.702  0.702  0.399  1.0
  P  P12  1  0.362  0.858  0.103  1.0
  P  P13  1  0.145  0.145  0.894  1.0
  P  P14  1  0.791  0.292  0.601  1.0
  O  O15  1  0.218  0.417  0.325  1.0
  O  O16  1  0.531  0.531  0.044  1.0
  O  O17  1  0.993  0.319  0.180  1.0
  O  O18  1  0.785  0.501  0.171  1.0
  O  O19  1  0.173  0.173  0.549  1.0
  O  O20  1  0.437  0.935  0.622  1.0
  O  O21  1  0.417  0.218  0.325  1.0
  O  O22  1  0.053  0.053  0.406  1.0
  O  O23  1  0.806  0.806  0.877  1.0
  O  O24  1  0.510  0.708  0.821  1.0
  O  O25  1  0.698  0.193  0.126  1.0
  O  O26  1  0.699  0.902  0.329  1.0
  O  O27  1  0.084  0.783  0.677  1.0
  O  O28  1  0.042  0.042  0.043  1.0
  O  O29  1  0.319  0.993  0.180  1.0
  O  O30  1  0.666  0.666  0.548  1.0
  O  O31  1  0.326  0.829  0.454  1.0
  O  O32  1  0.708  0.510  0.821  1.0
  O  O33  1  0.964  0.464  0.953  1.0
  O  O34  1  0.902  0.699  0.329  1.0
  O  O35  1  0.309  0.309  0.875  1.0
  O  O36  1  0.280  0.583  0.677  1.0
  O  O37  1  0.501  0.785  0.171  1.0
  O  O38  1  0.193  0.698  0.126  1.0
  O  O39  1  0.935  0.437  0.622  1.0
  O  O40  1  0.583  0.280  0.677  1.0
  O  O41  1  0.553  0.553  0.384  1.0
  O  O42  1  0.012  0.210  0.818  1.0
  O  O43  1  0.829  0.326  0.454  1.0
  O  O44  1  0.210  0.012  0.818  1.0
  O  O45  1  0.464  0.964  0.953  1.0
  O  O46  1  0.783  0.084  0.677  1.0
[/CIF]
.