The compound described by Fe7O9 crystallizes in the triclinic P1 space group. There are twenty-one inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a trigonal planar geometry to one O(21), one O(24), and one O(5) atom. In the second Fe site, Fe(2) is bonded in a distorted rectangular see-saw-like geometry to one O(26), one O(4), one O(5), and one O(6) atom. In the third Fe site, Fe(3) is bonded to one O(25), one O(3), one O(4), and one O(8) atom to form distorted FeO4 tetrahedra that share  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(17)O4 tetrahedra, and  a cornercorner with one Fe(6)O4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(27), one O(3), and one O(7) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  an edgeedge with one Fe(19)O5 trigonal bipyramid, and  an edgeedge with one Fe(20)O5 trigonal bipyramid. In the fifth Fe site, Fe(5) is bonded in a distorted trigonal planar geometry to one O(13), one O(2), and one O(9) atom. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(11), one O(12), and one O(4) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(8)O5 square pyramid,  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  a cornercorner with one Fe(20)O5 trigonal bipyramid, and  a cornercorner with one Fe(7)O5 trigonal bipyramid. In the seventh Fe site, Fe(7) is bonded to one O(10), one O(11), one O(13), one O(15), and one O(6) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(8)O5 square pyramid,  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  an edgeedge with one Fe(12)O5 trigonal bipyramid, and  an edgeedge with one Fe(13)O5 trigonal bipyramid. In the eighth Fe site, Fe(8) is bonded to one O(10), one O(12), one O(16), one O(5), and one O(9) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  a cornercorner with one Fe(7)O5 trigonal bipyramid,  an edgeedge with one Fe(14)O6 octahedra, and  an edgeedge with one Fe(9)O5 square pyramid. In the ninth Fe site, Fe(9) is bonded to one O(12), one O(14), one O(7), one O(8), and one O(9) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  an edgeedge with one Fe(14)O6 octahedra, and  an edgeedge with one Fe(8)O5 square pyramid. In the tenth Fe site, Fe(10) is bonded in a 3-coordinate geometry to one O(13), one O(17), one O(20), and one O(8) atom. In the eleventh Fe site, Fe(11) is bonded in a trigonal planar geometry to one O(10), one O(19), and one O(7) atom. In the twelfth Fe site, Fe(12) is bonded to one O(13), one O(15), one O(18), one O(19), and one O(20) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(19)O5 trigonal bipyramid,  an edgeedge with one Fe(14)O6 octahedra,  an edgeedge with one Fe(13)O5 trigonal bipyramid, and  an edgeedge with one Fe(7)O5 trigonal bipyramid. In the thirteenth Fe site, Fe(13) is bonded to one O(11), one O(15), one O(17), one O(18), and one O(22) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  a cornercorner with one Fe(20)O5 trigonal bipyramid,  an edgeedge with one Fe(12)O5 trigonal bipyramid, and  an edgeedge with one Fe(7)O5 trigonal bipyramid. In the fourteenth Fe site, Fe(14) is bonded to one O(14), one O(16), one O(19), one O(20), one O(24), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  an edgeedge with one Fe(8)O5 square pyramid,  an edgeedge with one Fe(9)O5 square pyramid,  an edgeedge with one Fe(12)O5 trigonal bipyramid, and  an edgeedge with one Fe(19)O5 trigonal bipyramid. In the fifteenth Fe site, Fe(15) is bonded in a 5-coordinate geometry to one O(12), one O(14), one O(16), one O(17), and one O(21) atom. In the sixteenth Fe site, Fe(16) is bonded to one O(15), one O(16), one O(23), and one O(26) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(14)O6 octahedra,  a cornercorner with one Fe(8)O5 square pyramid,  a cornercorner with one Fe(12)O5 trigonal bipyramid,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  a cornercorner with one Fe(19)O5 trigonal bipyramid,  a cornercorner with one Fe(20)O5 trigonal bipyramid, and  a cornercorner with one Fe(7)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 50°. In the seventeenth Fe site, Fe(17) is bonded to one O(14), one O(18), one O(25), and one O(27) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(14)O6 octahedra,  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(12)O5 trigonal bipyramid,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  a cornercorner with one Fe(19)O5 trigonal bipyramid, and  a cornercorner with one Fe(20)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 52°. In the eighteenth Fe site, Fe(18) is bonded in a distorted see-saw-like geometry to one O(20), one O(24), one O(25), and one O(26) atom. In the nineteenth Fe site, Fe(19) is bonded to one O(19), one O(2), one O(23), one O(24), and one O(27) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(12)O5 trigonal bipyramid,  an edgeedge with one Fe(14)O6 octahedra,  an edgeedge with one Fe(4)O5 square pyramid, and  an edgeedge with one Fe(20)O5 trigonal bipyramid. In the twentieth Fe site, Fe(20) is bonded to one O(1), one O(21), one O(22), one O(23), and one O(27) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  an edgeedge with one Fe(4)O5 square pyramid, and  an edgeedge with one Fe(19)O5 trigonal bipyramid. In the twenty-first Fe site, Fe(21) is bonded in a trigonal planar geometry to one O(22), one O(3), and one O(6) atom. There are twenty-seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(20), one Fe(4), and one Fe(6) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(19), one Fe(4), and one Fe(5) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(21), one Fe(3), and one Fe(4) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Fe(8) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(2), one Fe(21), and one Fe(7) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(11), one Fe(4), and one Fe(9) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Fe(10), one Fe(3), and one Fe(9) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Fe(14), one Fe(5), one Fe(8), and one Fe(9) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Fe(11), one Fe(7), and one Fe(8) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Fe(13), one Fe(6), and one Fe(7) atom. In the twelfth O site, O(12) is bonded in a distorted tetrahedral geometry to one Fe(15), one Fe(6), one Fe(8), and one Fe(9) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Fe(10), one Fe(12), one Fe(5), and one Fe(7) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Fe(14), one Fe(15), one Fe(17), and one Fe(9) atom. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Fe(12), one Fe(13), one Fe(16), and one Fe(7) atom. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Fe(14), one Fe(15), one Fe(16), and one Fe(8) atom. In the seventeenth O site, O(17) is bonded in a trigonal planar geometry to one Fe(10), one Fe(13), and one Fe(15) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Fe(12), one Fe(13), and one Fe(17) atom. In the nineteenth O site, O(19) is bonded to one Fe(11), one Fe(12), one Fe(14), and one Fe(19) atom to form edge-sharing OFe4 tetrahedra. In the twentieth O site, O(20) is bonded to one Fe(10), one Fe(12), one Fe(14), and one Fe(18) atom to form distorted edge-sharing OFe4 trigonal pyramids. In the twenty-first O site, O(21) is bonded in a trigonal planar geometry to one Fe(1), one Fe(15), and one Fe(20) atom. In the twenty-second O site, O(22) is bonded in a trigonal planar geometry to one Fe(13), one Fe(20), and one Fe(21) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Fe(16), one Fe(19), and one Fe(20) atom. In the twenty-fourth O site, O(24) is bonded to one Fe(1), one Fe(14), one Fe(18), and one Fe(19) atom to form edge-sharing OFe4 trigonal pyramids. In the twenty-fifth O site, O(25) is bonded in a trigonal planar geometry to one Fe(17), one Fe(18), and one Fe(3) atom. In the twenty-sixth O site, O(26) is bonded in a trigonal planar geometry to one Fe(16), one Fe(18), and one Fe(2) atom. In the twenty-seventh O site, O(27) is bonded in a rectangular see-saw-like geometry to one Fe(17), one Fe(19), one Fe(20), and one Fe(4) atom. is represented by the CIF card [CIF]
data_Fe7O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.585
_cell_length_b   8.620
_cell_length_c   8.778
_cell_angle_alpha   89.305
_cell_angle_beta   88.953
_cell_angle_gamma   89.393
_symmetry_Int_Tables_number   1
_cell_volume   649.387
_cell_formula_units_Z   3
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  0.513  0.490  0.969  1.0
  Fe  Fe1  1  0.634  0.177  0.085  1.0
  Fe  Fe2  1  0.328  0.918  0.128  1.0
  Fe  Fe3  1  0.088  0.629  0.144  1.0
  Fe  Fe4  1  0.756  0.757  0.258  1.0
  Fe  Fe5  1  0.269  0.264  0.270  1.0
  Fe  Fe6  1  0.905  0.130  0.357  1.0
  Fe  Fe7  1  0.630  0.403  0.363  1.0
  Fe  Fe8  1  0.356  0.627  0.412  1.0
  Fe  Fe9  1  0.491  0.965  0.471  1.0
  Fe  Fe10  1  0.964  0.518  0.470  1.0
  Fe  Fe11  1  0.878  0.872  0.600  1.0
  Fe  Fe12  1  0.145  0.085  0.630  1.0
  Fe  Fe13  1  0.628  0.619  0.631  1.0
  Fe  Fe14  1  0.404  0.332  0.642  1.0
  Fe  Fe15  1  0.774  0.238  0.738  1.0
  Fe  Fe16  1  0.246  0.735  0.777  1.0
  Fe  Fe17  1  0.591  0.882  0.841  1.0
  Fe  Fe18  1  0.874  0.594  0.876  1.0
  Fe  Fe19  1  0.138  0.361  0.914  1.0
  Fe  Fe20  1  0.004  0.034  0.008  1.0
  O  O21  1  0.158  0.391  0.130  1.0
  O  O22  1  0.858  0.670  0.081  1.0
  O  O23  1  0.120  0.868  0.113  1.0
  O  O24  1  0.408  0.119  0.166  1.0
  O  O25  1  0.594  0.394  0.149  1.0
  O  O26  1  0.850  0.122  0.144  1.0
  O  O27  1  0.142  0.611  0.370  1.0
  O  O28  1  0.410  0.822  0.309  1.0
  O  O29  1  0.620  0.621  0.401  1.0
  O  O30  1  0.844  0.347  0.385  1.0
  O  O31  1  0.127  0.146  0.395  1.0
  O  O32  1  0.396  0.392  0.404  1.0
  O  O33  1  0.792  0.933  0.387  1.0
  O  O34  1  0.384  0.630  0.631  1.0
  O  O35  1  0.904  0.112  0.609  1.0
  O  O36  1  0.639  0.384  0.625  1.0
  O  O37  1  0.368  0.108  0.599  1.0
  O  O38  1  0.113  0.866  0.662  1.0
  O  O39  1  0.866  0.638  0.642  1.0
  O  O40  1  0.622  0.858  0.630  1.0
  O  O41  1  0.355  0.385  0.855  1.0
  O  O42  1  0.122  0.148  0.846  1.0
  O  O43  1  0.895  0.372  0.860  1.0
  O  O44  1  0.643  0.651  0.860  1.0
  O  O45  1  0.387  0.839  0.921  1.0
  O  O46  1  0.672  0.083  0.871  1.0
  O  O47  1  0.107  0.599  0.884  1.0
[/CIF]
.
The compound described by Fe7O9 crystallizes in the triclinic P1 space group. There are twenty-one inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a trigonal planar geometry to one O(21), one O(24), and one O(5) atom. In the second Fe site, Fe(2) is bonded in a distorted rectangular see-saw-like geometry to one O(26), one O(4), one O(5), and one O(6) atom. In the third Fe site, Fe(3) is bonded to one O(25), one O(3), one O(4), and one O(8) atom to form distorted FeO4 tetrahedra that share  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(17)O4 tetrahedra, and  a cornercorner with one Fe(6)O4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(27), one O(3), and one O(7) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  an edgeedge with one Fe(19)O5 trigonal bipyramid, and  an edgeedge with one Fe(20)O5 trigonal bipyramid. In the fifth Fe site, Fe(5) is bonded in a distorted trigonal planar geometry to one O(13), one O(2), and one O(9) atom. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(11), one O(12), and one O(4) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(8)O5 square pyramid,  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  a cornercorner with one Fe(20)O5 trigonal bipyramid, and  a cornercorner with one Fe(7)O5 trigonal bipyramid. In the seventh Fe site, Fe(7) is bonded to one O(10), one O(11), one O(13), one O(15), and one O(6) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(8)O5 square pyramid,  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  an edgeedge with one Fe(12)O5 trigonal bipyramid, and  an edgeedge with one Fe(13)O5 trigonal bipyramid. In the eighth Fe site, Fe(8) is bonded to one O(10), one O(12), one O(16), one O(5), and one O(9) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  a cornercorner with one Fe(7)O5 trigonal bipyramid,  an edgeedge with one Fe(14)O6 octahedra, and  an edgeedge with one Fe(9)O5 square pyramid. In the ninth Fe site, Fe(9) is bonded to one O(12), one O(14), one O(7), one O(8), and one O(9) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  an edgeedge with one Fe(14)O6 octahedra, and  an edgeedge with one Fe(8)O5 square pyramid. In the tenth Fe site, Fe(10) is bonded in a 3-coordinate geometry to one O(13), one O(17), one O(20), and one O(8) atom. In the eleventh Fe site, Fe(11) is bonded in a trigonal planar geometry to one O(10), one O(19), and one O(7) atom. In the twelfth Fe site, Fe(12) is bonded to one O(13), one O(15), one O(18), one O(19), and one O(20) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(19)O5 trigonal bipyramid,  an edgeedge with one Fe(14)O6 octahedra,  an edgeedge with one Fe(13)O5 trigonal bipyramid, and  an edgeedge with one Fe(7)O5 trigonal bipyramid. In the thirteenth Fe site, Fe(13) is bonded to one O(11), one O(15), one O(17), one O(18), and one O(22) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  a cornercorner with one Fe(20)O5 trigonal bipyramid,  an edgeedge with one Fe(12)O5 trigonal bipyramid, and  an edgeedge with one Fe(7)O5 trigonal bipyramid. In the fourteenth Fe site, Fe(14) is bonded to one O(14), one O(16), one O(19), one O(20), one O(24), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  an edgeedge with one Fe(8)O5 square pyramid,  an edgeedge with one Fe(9)O5 square pyramid,  an edgeedge with one Fe(12)O5 trigonal bipyramid, and  an edgeedge with one Fe(19)O5 trigonal bipyramid. In the fifteenth Fe site, Fe(15) is bonded in a 5-coordinate geometry to one O(12), one O(14), one O(16), one O(17), and one O(21) atom. In the sixteenth Fe site, Fe(16) is bonded to one O(15), one O(16), one O(23), and one O(26) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(14)O6 octahedra,  a cornercorner with one Fe(8)O5 square pyramid,  a cornercorner with one Fe(12)O5 trigonal bipyramid,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  a cornercorner with one Fe(19)O5 trigonal bipyramid,  a cornercorner with one Fe(20)O5 trigonal bipyramid, and  a cornercorner with one Fe(7)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 50°. In the seventeenth Fe site, Fe(17) is bonded to one O(14), one O(18), one O(25), and one O(27) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(14)O6 octahedra,  a cornercorner with one Fe(4)O5 square pyramid,  a cornercorner with one Fe(9)O5 square pyramid,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(12)O5 trigonal bipyramid,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  a cornercorner with one Fe(19)O5 trigonal bipyramid, and  a cornercorner with one Fe(20)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 52°. In the eighteenth Fe site, Fe(18) is bonded in a distorted see-saw-like geometry to one O(20), one O(24), one O(25), and one O(26) atom. In the nineteenth Fe site, Fe(19) is bonded to one O(19), one O(2), one O(23), one O(24), and one O(27) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(12)O5 trigonal bipyramid,  an edgeedge with one Fe(14)O6 octahedra,  an edgeedge with one Fe(4)O5 square pyramid, and  an edgeedge with one Fe(20)O5 trigonal bipyramid. In the twentieth Fe site, Fe(20) is bonded to one O(1), one O(21), one O(22), one O(23), and one O(27) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(16)O4 tetrahedra,  a cornercorner with one Fe(17)O4 tetrahedra,  a cornercorner with one Fe(6)O4 tetrahedra,  a cornercorner with one Fe(13)O5 trigonal bipyramid,  an edgeedge with one Fe(4)O5 square pyramid, and  an edgeedge with one Fe(19)O5 trigonal bipyramid. In the twenty-first Fe site, Fe(21) is bonded in a trigonal planar geometry to one O(22), one O(3), and one O(6) atom. There are twenty-seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(20), one Fe(4), and one Fe(6) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(19), one Fe(4), and one Fe(5) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(21), one Fe(3), and one Fe(4) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Fe(8) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(2), one Fe(21), and one Fe(7) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(11), one Fe(4), and one Fe(9) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Fe(10), one Fe(3), and one Fe(9) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Fe(14), one Fe(5), one Fe(8), and one Fe(9) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Fe(11), one Fe(7), and one Fe(8) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Fe(13), one Fe(6), and one Fe(7) atom. In the twelfth O site, O(12) is bonded in a distorted tetrahedral geometry to one Fe(15), one Fe(6), one Fe(8), and one Fe(9) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Fe(10), one Fe(12), one Fe(5), and one Fe(7) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Fe(14), one Fe(15), one Fe(17), and one Fe(9) atom. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Fe(12), one Fe(13), one Fe(16), and one Fe(7) atom. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Fe(14), one Fe(15), one Fe(16), and one Fe(8) atom. In the seventeenth O site, O(17) is bonded in a trigonal planar geometry to one Fe(10), one Fe(13), and one Fe(15) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Fe(12), one Fe(13), and one Fe(17) atom. In the nineteenth O site, O(19) is bonded to one Fe(11), one Fe(12), one Fe(14), and one Fe(19) atom to form edge-sharing OFe4 tetrahedra. In the twentieth O site, O(20) is bonded to one Fe(10), one Fe(12), one Fe(14), and one Fe(18) atom to form distorted edge-sharing OFe4 trigonal pyramids. In the twenty-first O site, O(21) is bonded in a trigonal planar geometry to one Fe(1), one Fe(15), and one Fe(20) atom. In the twenty-second O site, O(22) is bonded in a trigonal planar geometry to one Fe(13), one Fe(20), and one Fe(21) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Fe(16), one Fe(19), and one Fe(20) atom. In the twenty-fourth O site, O(24) is bonded to one Fe(1), one Fe(14), one Fe(18), and one Fe(19) atom to form edge-sharing OFe4 trigonal pyramids. In the twenty-fifth O site, O(25) is bonded in a trigonal planar geometry to one Fe(17), one Fe(18), and one Fe(3) atom. In the twenty-sixth O site, O(26) is bonded in a trigonal planar geometry to one Fe(16), one Fe(18), and one Fe(2) atom. In the twenty-seventh O site, O(27) is bonded in a rectangular see-saw-like geometry to one Fe(17), one Fe(19), one Fe(20), and one Fe(4) atom. is represented by the CIF card [CIF]
data_Fe7O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.585
_cell_length_b   8.620
_cell_length_c   8.778
_cell_angle_alpha   89.305
_cell_angle_beta   88.953
_cell_angle_gamma   89.393
_symmetry_Int_Tables_number   1
_cell_volume   649.387
_cell_formula_units_Z   3
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  0.513  0.490  0.969  1.0
  Fe  Fe1  1  0.634  0.177  0.085  1.0
  Fe  Fe2  1  0.328  0.918  0.128  1.0
  Fe  Fe3  1  0.088  0.629  0.144  1.0
  Fe  Fe4  1  0.756  0.757  0.258  1.0
  Fe  Fe5  1  0.269  0.264  0.270  1.0
  Fe  Fe6  1  0.905  0.130  0.357  1.0
  Fe  Fe7  1  0.630  0.403  0.363  1.0
  Fe  Fe8  1  0.356  0.627  0.412  1.0
  Fe  Fe9  1  0.491  0.965  0.471  1.0
  Fe  Fe10  1  0.964  0.518  0.470  1.0
  Fe  Fe11  1  0.878  0.872  0.600  1.0
  Fe  Fe12  1  0.145  0.085  0.630  1.0
  Fe  Fe13  1  0.628  0.619  0.631  1.0
  Fe  Fe14  1  0.404  0.332  0.642  1.0
  Fe  Fe15  1  0.774  0.238  0.738  1.0
  Fe  Fe16  1  0.246  0.735  0.777  1.0
  Fe  Fe17  1  0.591  0.882  0.841  1.0
  Fe  Fe18  1  0.874  0.594  0.876  1.0
  Fe  Fe19  1  0.138  0.361  0.914  1.0
  Fe  Fe20  1  0.004  0.034  0.008  1.0
  O  O21  1  0.158  0.391  0.130  1.0
  O  O22  1  0.858  0.670  0.081  1.0
  O  O23  1  0.120  0.868  0.113  1.0
  O  O24  1  0.408  0.119  0.166  1.0
  O  O25  1  0.594  0.394  0.149  1.0
  O  O26  1  0.850  0.122  0.144  1.0
  O  O27  1  0.142  0.611  0.370  1.0
  O  O28  1  0.410  0.822  0.309  1.0
  O  O29  1  0.620  0.621  0.401  1.0
  O  O30  1  0.844  0.347  0.385  1.0
  O  O31  1  0.127  0.146  0.395  1.0
  O  O32  1  0.396  0.392  0.404  1.0
  O  O33  1  0.792  0.933  0.387  1.0
  O  O34  1  0.384  0.630  0.631  1.0
  O  O35  1  0.904  0.112  0.609  1.0
  O  O36  1  0.639  0.384  0.625  1.0
  O  O37  1  0.368  0.108  0.599  1.0
  O  O38  1  0.113  0.866  0.662  1.0
  O  O39  1  0.866  0.638  0.642  1.0
  O  O40  1  0.622  0.858  0.630  1.0
  O  O41  1  0.355  0.385  0.855  1.0
  O  O42  1  0.122  0.148  0.846  1.0
  O  O43  1  0.895  0.372  0.860  1.0
  O  O44  1  0.643  0.651  0.860  1.0
  O  O45  1  0.387  0.839  0.921  1.0
  O  O46  1  0.672  0.083  0.871  1.0
  O  O47  1  0.107  0.599  0.884  1.0
[/CIF]
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