The crystal structure described by Ti2Fe4O9 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(14), one O(16), one O(18), one O(2), and one O(7) atom to form distorted TiO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra,  an edgeedge with one Fe(8)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-60°. In the second Ti site, Ti(2) is bonded to one O(11), one O(15), one O(2), one O(3), one O(4), and one O(7) atom to form TiO6 octahedra that share  a cornercorner with one Fe(6)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra,  a cornercorner with one Fe(8)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-63°. In the third Ti site, Ti(3) is bonded to one O(13), one O(16), one O(18), one O(6), one O(8), and one O(9) atom to form distorted TiO6 octahedra that share  a cornercorner with one Fe(6)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra,  a cornercorner with one Fe(8)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and  a faceface with one Fe(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-63°. In the fourth Ti site, Ti(4) is bonded to one O(1), one O(10), one O(12), one O(14), one O(17), and one O(5) atom to form distorted TiO6 octahedra that share  a cornercorner with one Fe(6)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra,  a cornercorner with one Fe(8)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and  a faceface with one Fe(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-62°. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(14), one O(18), one O(2), one O(5), one O(7), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with two equivalent Fe(8)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and  a faceface with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-69°. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(11), one O(13), one O(3), and one O(6) atom to form FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with two equivalent Fe(8)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-66°. In the third Fe site, Fe(3) is bonded to one O(10), one O(13), one O(3), one O(4), one O(5), and one O(6) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra,  an edgeedge with one Fe(8)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-69°. In the fourth Fe site, Fe(4) is bonded to one O(12), one O(15), one O(16), one O(17), one O(4), and one O(8) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with two equivalent Fe(8)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and  a faceface with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-64°. In the fifth Fe site, Fe(5) is bonded to one O(11), one O(12), one O(15), one O(17), one O(8), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra,  an edgeedge with one Fe(8)O6 octahedra, and  a faceface with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-62°. In the sixth Fe site, Fe(6) is bonded to one O(10), one O(11), one O(2), one O(4), one O(7), and one O(8) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Fe(5)O6 octahedra, and  a faceface with one Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. In the seventh Fe site, Fe(7) is bonded to one O(13), one O(14), one O(15), one O(16), one O(6), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Fe(5)O6 octahedra, and  a faceface with one Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-59°. In the eighth Fe site, Fe(8) is bonded to one O(1), one O(12), one O(17), one O(18), one O(3), and one O(5) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Fe(5)O6 octahedra, and  a faceface with one Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-59°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(4), one Fe(2), and one Fe(8) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Fe(1), and one Fe(6) atom. In the third O site, O(3) is bonded to one Ti(2), one Fe(2), one Fe(3), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(18)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid, corners with two equivalent O(4)TiFe3 trigonal pyramids, and  an edgeedge with one O(5)TiFe3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Ti(2), one Fe(3), one Fe(4), and one Fe(6) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(16)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, and corners with two equivalent O(3)TiFe3 trigonal pyramids. In the fifth O site, O(5) is bonded to one Ti(4), one Fe(1), one Fe(3), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(9)TiFe3 trigonal pyramid, corners with two equivalent O(18)Ti2Fe2 trigonal pyramids, corners with two equivalent O(17)TiFe3 trigonal pyramids,  an edgeedge with one O(14)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(12)TiFe3 trigonal pyramid, and  an edgeedge with one O(3)TiFe3 trigonal pyramid. In the sixth O site, O(6) is bonded in a see-saw-like geometry to one Ti(3), one Fe(2), one Fe(3), and one Fe(7) atom. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(2), one Fe(1), and one Fe(6) atom. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Ti(3), one Fe(4), one Fe(5), and one Fe(6) atom. In the ninth O site, O(9) is bonded to one Ti(3), one Fe(1), one Fe(5), and one Fe(7) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, corners with two equivalent O(14)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(16)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(18)Ti2Fe2 trigonal pyramid. In the tenth O site, O(10) is bonded in a distorted see-saw-like geometry to one Ti(4), one Fe(2), one Fe(3), and one Fe(6) atom. In the eleventh O site, O(11) is bonded in a distorted see-saw-like geometry to one Ti(2), one Fe(2), one Fe(5), and one Fe(6) atom. In the twelfth O site, O(12) is bonded to one Ti(4), one Fe(4), one Fe(5), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(14)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(16)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(18)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(9)TiFe3 trigonal pyramid,  an edgeedge with one O(5)TiFe3 trigonal pyramid, and edges with two equivalent O(17)TiFe3 trigonal pyramids. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Ti(3), one Fe(2), one Fe(3), and one Fe(7) atom. In the fourteenth O site, O(14) is bonded to one Ti(1), one Ti(4), one Fe(1), and one Fe(7) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid, corners with two equivalent O(9)TiFe3 trigonal pyramids,  an edgeedge with one O(16)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(18)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(5)TiFe3 trigonal pyramid. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Ti(2), one Fe(4), one Fe(5), and one Fe(7) atom. In the sixteenth O site, O(16) is bonded to one Ti(1), one Ti(3), one Fe(4), and one Fe(7) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid, corners with two equivalent O(18)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(14)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(9)TiFe3 trigonal pyramid. In the seventeenth O site, O(17) is bonded to one Ti(4), one Fe(4), one Fe(5), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(14)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(16)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(18)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(9)TiFe3 trigonal pyramid, corners with two equivalent O(5)TiFe3 trigonal pyramids, and edges with two equivalent O(12)TiFe3 trigonal pyramids. In the eighteenth O site, O(18) is bonded to one Ti(1), one Ti(3), one Fe(1), and one Fe(8) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid, corners with two equivalent O(16)Ti2Fe2 trigonal pyramids, corners with two equivalent O(5)TiFe3 trigonal pyramids,  an edgeedge with one O(14)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(9)TiFe3 trigonal pyramid. is represented by the CIF file [CIF]
data_Ti2Fe4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.519
_cell_length_b   7.599
_cell_length_c   8.888
_cell_angle_alpha   113.313
_cell_angle_beta   105.116
_cell_angle_gamma   95.851
_symmetry_Int_Tables_number   1
_cell_volume   321.503
_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
  Ti  Ti0  1  0.298  0.362  0.007  1.0
  Ti  Ti1  1  0.972  0.522  0.336  1.0
  Ti  Ti2  1  0.614  0.178  0.662  1.0
  Ti  Ti3  1  0.300  0.867  0.004  1.0
  Fe  Fe4  1  0.717  0.141  0.001  1.0
  Fe  Fe5  1  0.364  0.819  0.335  1.0
  Fe  Fe6  1  0.951  0.017  0.330  1.0
  Fe  Fe7  1  0.043  0.476  0.668  1.0
  Fe  Fe8  1  0.619  0.684  0.661  1.0
  Fe  Fe9  1  0.384  0.316  0.338  1.0
  Fe  Fe10  1  0.028  0.977  0.664  1.0
  Fe  Fe11  1  0.714  0.645  0.999  1.0
  O  O12  1  0.390  0.632  0.091  1.0
  O  O13  1  0.084  0.331  0.127  1.0
  O  O14  1  0.957  0.694  0.228  1.0
  O  O15  1  0.057  0.328  0.434  1.0
  O  O16  1  0.679  0.929  0.090  1.0
  O  O17  1  0.737  0.995  0.478  1.0
  O  O18  1  0.619  0.365  0.200  1.0
  O  O19  1  0.644  0.378  0.584  1.0
  O  O20  1  0.729  0.976  0.759  1.0
  O  O21  1  0.262  0.005  0.217  1.0
  O  O22  1  0.363  0.628  0.443  1.0
  O  O23  1  0.395  0.649  0.794  1.0
  O  O24  1  0.279  0.031  0.552  1.0
  O  O25  1  0.278  0.042  0.902  1.0
  O  O26  1  0.926  0.680  0.555  1.0
  O  O27  1  0.051  0.291  0.781  1.0
  O  O28  1  0.952  0.692  0.874  1.0
  O  O29  1  0.596  0.349  0.886  1.0
[/CIF]
.
The crystal structure described by Ti2Fe4O9 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(14), one O(16), one O(18), one O(2), and one O(7) atom to form distorted TiO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra,  an edgeedge with one Fe(8)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-60°. In the second Ti site, Ti(2) is bonded to one O(11), one O(15), one O(2), one O(3), one O(4), and one O(7) atom to form TiO6 octahedra that share  a cornercorner with one Fe(6)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra,  a cornercorner with one Fe(8)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-63°. In the third Ti site, Ti(3) is bonded to one O(13), one O(16), one O(18), one O(6), one O(8), and one O(9) atom to form distorted TiO6 octahedra that share  a cornercorner with one Fe(6)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra,  a cornercorner with one Fe(8)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and  a faceface with one Fe(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-63°. In the fourth Ti site, Ti(4) is bonded to one O(1), one O(10), one O(12), one O(14), one O(17), and one O(5) atom to form distorted TiO6 octahedra that share  a cornercorner with one Fe(6)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra,  a cornercorner with one Fe(8)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and  a faceface with one Fe(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-62°. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(14), one O(18), one O(2), one O(5), one O(7), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with two equivalent Fe(8)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and  a faceface with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-69°. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(11), one O(13), one O(3), and one O(6) atom to form FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with two equivalent Fe(8)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-66°. In the third Fe site, Fe(3) is bonded to one O(10), one O(13), one O(3), one O(4), one O(5), and one O(6) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra,  an edgeedge with one Fe(8)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-69°. In the fourth Fe site, Fe(4) is bonded to one O(12), one O(15), one O(16), one O(17), one O(4), and one O(8) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with two equivalent Fe(8)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and  a faceface with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-64°. In the fifth Fe site, Fe(5) is bonded to one O(11), one O(12), one O(15), one O(17), one O(8), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra,  an edgeedge with one Fe(8)O6 octahedra, and  a faceface with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-62°. In the sixth Fe site, Fe(6) is bonded to one O(10), one O(11), one O(2), one O(4), one O(7), and one O(8) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Fe(5)O6 octahedra, and  a faceface with one Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. In the seventh Fe site, Fe(7) is bonded to one O(13), one O(14), one O(15), one O(16), one O(6), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Fe(5)O6 octahedra, and  a faceface with one Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-59°. In the eighth Fe site, Fe(8) is bonded to one O(1), one O(12), one O(17), one O(18), one O(3), and one O(5) atom to form distorted FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Fe(5)O6 octahedra, and  a faceface with one Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-59°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(4), one Fe(2), and one Fe(8) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Fe(1), and one Fe(6) atom. In the third O site, O(3) is bonded to one Ti(2), one Fe(2), one Fe(3), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(18)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid, corners with two equivalent O(4)TiFe3 trigonal pyramids, and  an edgeedge with one O(5)TiFe3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Ti(2), one Fe(3), one Fe(4), and one Fe(6) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(16)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, and corners with two equivalent O(3)TiFe3 trigonal pyramids. In the fifth O site, O(5) is bonded to one Ti(4), one Fe(1), one Fe(3), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(9)TiFe3 trigonal pyramid, corners with two equivalent O(18)Ti2Fe2 trigonal pyramids, corners with two equivalent O(17)TiFe3 trigonal pyramids,  an edgeedge with one O(14)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(12)TiFe3 trigonal pyramid, and  an edgeedge with one O(3)TiFe3 trigonal pyramid. In the sixth O site, O(6) is bonded in a see-saw-like geometry to one Ti(3), one Fe(2), one Fe(3), and one Fe(7) atom. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(2), one Fe(1), and one Fe(6) atom. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Ti(3), one Fe(4), one Fe(5), and one Fe(6) atom. In the ninth O site, O(9) is bonded to one Ti(3), one Fe(1), one Fe(5), and one Fe(7) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, corners with two equivalent O(14)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(16)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(18)Ti2Fe2 trigonal pyramid. In the tenth O site, O(10) is bonded in a distorted see-saw-like geometry to one Ti(4), one Fe(2), one Fe(3), and one Fe(6) atom. In the eleventh O site, O(11) is bonded in a distorted see-saw-like geometry to one Ti(2), one Fe(2), one Fe(5), and one Fe(6) atom. In the twelfth O site, O(12) is bonded to one Ti(4), one Fe(4), one Fe(5), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(14)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(16)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(18)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(9)TiFe3 trigonal pyramid,  an edgeedge with one O(5)TiFe3 trigonal pyramid, and edges with two equivalent O(17)TiFe3 trigonal pyramids. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Ti(3), one Fe(2), one Fe(3), and one Fe(7) atom. In the fourteenth O site, O(14) is bonded to one Ti(1), one Ti(4), one Fe(1), and one Fe(7) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid, corners with two equivalent O(9)TiFe3 trigonal pyramids,  an edgeedge with one O(16)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(18)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(5)TiFe3 trigonal pyramid. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Ti(2), one Fe(4), one Fe(5), and one Fe(7) atom. In the sixteenth O site, O(16) is bonded to one Ti(1), one Ti(3), one Fe(4), and one Fe(7) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid, corners with two equivalent O(18)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(14)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(9)TiFe3 trigonal pyramid. In the seventeenth O site, O(17) is bonded to one Ti(4), one Fe(4), one Fe(5), and one Fe(8) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(14)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(16)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(18)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(9)TiFe3 trigonal pyramid, corners with two equivalent O(5)TiFe3 trigonal pyramids, and edges with two equivalent O(12)TiFe3 trigonal pyramids. In the eighteenth O site, O(18) is bonded to one Ti(1), one Ti(3), one Fe(1), and one Fe(8) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(12)TiFe3 trigonal pyramid,  a cornercorner with one O(17)TiFe3 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid, corners with two equivalent O(16)Ti2Fe2 trigonal pyramids, corners with two equivalent O(5)TiFe3 trigonal pyramids,  an edgeedge with one O(14)Ti2Fe2 trigonal pyramid, and  an edgeedge with one O(9)TiFe3 trigonal pyramid. is represented by the CIF file [CIF]
data_Ti2Fe4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.519
_cell_length_b   7.599
_cell_length_c   8.888
_cell_angle_alpha   113.313
_cell_angle_beta   105.116
_cell_angle_gamma   95.851
_symmetry_Int_Tables_number   1
_cell_volume   321.503
_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
  Ti  Ti0  1  0.298  0.362  0.007  1.0
  Ti  Ti1  1  0.972  0.522  0.336  1.0
  Ti  Ti2  1  0.614  0.178  0.662  1.0
  Ti  Ti3  1  0.300  0.867  0.004  1.0
  Fe  Fe4  1  0.717  0.141  0.001  1.0
  Fe  Fe5  1  0.364  0.819  0.335  1.0
  Fe  Fe6  1  0.951  0.017  0.330  1.0
  Fe  Fe7  1  0.043  0.476  0.668  1.0
  Fe  Fe8  1  0.619  0.684  0.661  1.0
  Fe  Fe9  1  0.384  0.316  0.338  1.0
  Fe  Fe10  1  0.028  0.977  0.664  1.0
  Fe  Fe11  1  0.714  0.645  0.999  1.0
  O  O12  1  0.390  0.632  0.091  1.0
  O  O13  1  0.084  0.331  0.127  1.0
  O  O14  1  0.957  0.694  0.228  1.0
  O  O15  1  0.057  0.328  0.434  1.0
  O  O16  1  0.679  0.929  0.090  1.0
  O  O17  1  0.737  0.995  0.478  1.0
  O  O18  1  0.619  0.365  0.200  1.0
  O  O19  1  0.644  0.378  0.584  1.0
  O  O20  1  0.729  0.976  0.759  1.0
  O  O21  1  0.262  0.005  0.217  1.0
  O  O22  1  0.363  0.628  0.443  1.0
  O  O23  1  0.395  0.649  0.794  1.0
  O  O24  1  0.279  0.031  0.552  1.0
  O  O25  1  0.278  0.042  0.902  1.0
  O  O26  1  0.926  0.680  0.555  1.0
  O  O27  1  0.051  0.291  0.781  1.0
  O  O28  1  0.952  0.692  0.874  1.0
  O  O29  1  0.596  0.349  0.886  1.0
[/CIF]
.