The material structure described by Ti2Fe4O9 is Ilmenite-like structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(4), one O(5), one O(6), and two equivalent O(2) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with six equivalent Fe(1)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-61°. In the second Ti site, Ti(2) is bonded to one O(3), one O(7), two equivalent O(8), and two equivalent O(9) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra, corners with five equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, edges with two equivalent Ti(2)O6 octahedra, and  a faceface with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-58°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with six equivalent Ti(1)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-64°. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(4)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-64°. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and  a faceface with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-58°. In the fourth Fe site, Fe(4) is bonded to one O(6), one O(9), two equivalent O(7), and two equivalent O(8) atoms to form FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with five equivalent Ti(2)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and  a faceface with one Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-63°. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ti(1), one Fe(1), one Fe(2), and one Fe(3) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(9)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(6)TiFe3 trigonal pyramid,  a cornercorner with one O(7)TiFe3 trigonal pyramid, corners with three equivalent O(3)TiFe3 trigonal pyramids, corners with four equivalent O(5)TiFe3 trigonal pyramids,  an edgeedge with one O(6)TiFe3 trigonal pyramid, and edges with two equivalent O(4)TiFe3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ti(1), one Fe(1), and one Fe(3) atom. In the third O site, O(3) is bonded to one Ti(2), one Fe(1), one Fe(2), and one Fe(3) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, corners with two equivalent O(8)Ti2Fe2 trigonal pyramids, corners with two equivalent O(6)TiFe3 trigonal pyramids, corners with three equivalent O(9)Ti2Fe2 trigonal pyramids, corners with three equivalent O(1)TiFe3 trigonal pyramids,  an edgeedge with one O(4)TiFe3 trigonal pyramid,  an edgeedge with one O(5)TiFe3 trigonal pyramid, and  an edgeedge with one O(7)TiFe3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Ti(1), one Fe(1), one Fe(2), and one Fe(3) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(9)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid,  a cornercorner with one O(7)TiFe3 trigonal pyramid, corners with two equivalent O(5)TiFe3 trigonal pyramids, corners with three equivalent O(6)TiFe3 trigonal pyramids,  an edgeedge with one O(3)TiFe3 trigonal pyramid,  an edgeedge with one O(5)TiFe3 trigonal pyramid, and edges with two equivalent O(1)TiFe3 trigonal pyramids. In the fifth O site, O(5) is bonded to one Ti(1), one Fe(2), and two equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OTiFe3 trigonal pyramids. In the sixth O site, O(6) is bonded to one Ti(1), one Fe(2), one Fe(3), and one Fe(4) atom to form OTiFe3 trigonal pyramids that share  a cornercorner with one O(1)TiFe3 trigonal pyramid, corners with two equivalent O(8)Ti2Fe2 trigonal pyramids, corners with two equivalent O(3)TiFe3 trigonal pyramids, corners with three equivalent O(4)TiFe3 trigonal pyramids, corners with three equivalent O(7)TiFe3 trigonal pyramids,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(1)TiFe3 trigonal pyramid, and  an edgeedge with one O(5)TiFe3 trigonal pyramid. In the seventh O site, O(7) is bonded to one Ti(2), one Fe(2), and two equivalent Fe(4) atoms to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(1)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, corners with two equivalent O(9)Ti2Fe2 trigonal pyramids, corners with three equivalent O(6)TiFe3 trigonal pyramids, corners with four equivalent O(8)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(8)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(3)TiFe3 trigonal pyramid, and  an edgeedge with one O(7)TiFe3 trigonal pyramid. In the eighth O site, O(8) is bonded to two equivalent Ti(2) and two equivalent Fe(4) atoms to form distorted OTi2Fe2 trigonal pyramids that share corners with two equivalent O(3)TiFe3 trigonal pyramids, corners with two equivalent O(6)TiFe3 trigonal pyramids, corners with four equivalent O(9)Ti2Fe2 trigonal pyramids, corners with four equivalent O(7)TiFe3 trigonal pyramids,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(7)TiFe3 trigonal pyramid, and edges with two equivalent O(8)Ti2Fe2 trigonal pyramids. In the ninth O site, O(9) is bonded to two equivalent Ti(2), one Fe(3), and one Fe(4) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(1)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid, corners with two equivalent O(7)TiFe3 trigonal pyramids, corners with three equivalent O(3)TiFe3 trigonal pyramids, corners with four equivalent O(8)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(8)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(6)TiFe3 trigonal pyramid, and  an edgeedge with one O(7)TiFe3 trigonal pyramid. is represented by the CIF file [CIF]
data_Ti2Fe4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.145
_cell_length_b   5.516
_cell_length_c   11.665
_cell_angle_alpha   97.412
_cell_angle_beta   102.653
_cell_angle_gamma   91.138
_symmetry_Int_Tables_number   1
_cell_volume   319.930
_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  0.048  0.334  0.097  1.0
  Ti  Ti1  1  0.720  0.010  0.427  1.0
  Ti  Ti2  1  0.280  0.990  0.573  1.0
  Ti  Ti3  1  0.952  0.666  0.903  1.0
  Fe  Fe4  1  0.550  0.842  0.096  1.0
  Fe  Fe5  1  0.618  0.332  0.236  1.0
  Fe  Fe6  1  0.122  0.817  0.236  1.0
  Fe  Fe7  1  0.779  0.489  0.568  1.0
  Fe  Fe8  1  0.221  0.511  0.432  1.0
  Fe  Fe9  1  0.878  0.183  0.764  1.0
  Fe  Fe10  1  0.382  0.668  0.764  1.0
  Fe  Fe11  1  0.450  0.158  0.904  1.0
  O  O12  1  0.379  0.577  0.167  1.0
  O  O13  1  0.899  0.683  0.059  1.0
  O  O14  1  0.790  0.973  0.274  1.0
  O  O15  1  0.262  0.092  0.167  1.0
  O  O16  1  0.699  0.191  0.070  1.0
  O  O17  1  0.977  0.486  0.262  1.0
  O  O18  1  0.560  0.336  0.396  1.0
  O  O19  1  0.939  0.770  0.498  1.0
  O  O20  1  0.366  0.859  0.398  1.0
  O  O21  1  0.634  0.141  0.602  1.0
  O  O22  1  0.061  0.230  0.502  1.0
  O  O23  1  0.440  0.664  0.604  1.0
  O  O24  1  0.023  0.514  0.738  1.0
  O  O25  1  0.301  0.809  0.930  1.0
  O  O26  1  0.738  0.908  0.833  1.0
  O  O27  1  0.210  0.027  0.726  1.0
  O  O28  1  0.101  0.317  0.941  1.0
  O  O29  1  0.621  0.423  0.833  1.0
[/CIF]
.
The material structure described by Ti2Fe4O9 is Ilmenite-like structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(4), one O(5), one O(6), and two equivalent O(2) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with six equivalent Fe(1)O6 octahedra,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-61°. In the second Ti site, Ti(2) is bonded to one O(3), one O(7), two equivalent O(8), and two equivalent O(9) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra, corners with five equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, edges with two equivalent Ti(2)O6 octahedra, and  a faceface with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-58°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with six equivalent Ti(1)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-64°. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(4)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-64°. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and  a faceface with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-58°. In the fourth Fe site, Fe(4) is bonded to one O(6), one O(9), two equivalent O(7), and two equivalent O(8) atoms to form FeO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with five equivalent Ti(2)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and  a faceface with one Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-63°. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ti(1), one Fe(1), one Fe(2), and one Fe(3) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(9)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(6)TiFe3 trigonal pyramid,  a cornercorner with one O(7)TiFe3 trigonal pyramid, corners with three equivalent O(3)TiFe3 trigonal pyramids, corners with four equivalent O(5)TiFe3 trigonal pyramids,  an edgeedge with one O(6)TiFe3 trigonal pyramid, and edges with two equivalent O(4)TiFe3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ti(1), one Fe(1), and one Fe(3) atom. In the third O site, O(3) is bonded to one Ti(2), one Fe(1), one Fe(2), and one Fe(3) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, corners with two equivalent O(8)Ti2Fe2 trigonal pyramids, corners with two equivalent O(6)TiFe3 trigonal pyramids, corners with three equivalent O(9)Ti2Fe2 trigonal pyramids, corners with three equivalent O(1)TiFe3 trigonal pyramids,  an edgeedge with one O(4)TiFe3 trigonal pyramid,  an edgeedge with one O(5)TiFe3 trigonal pyramid, and  an edgeedge with one O(7)TiFe3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Ti(1), one Fe(1), one Fe(2), and one Fe(3) atom to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(9)Ti2Fe2 trigonal pyramid,  a cornercorner with one O(3)TiFe3 trigonal pyramid,  a cornercorner with one O(7)TiFe3 trigonal pyramid, corners with two equivalent O(5)TiFe3 trigonal pyramids, corners with three equivalent O(6)TiFe3 trigonal pyramids,  an edgeedge with one O(3)TiFe3 trigonal pyramid,  an edgeedge with one O(5)TiFe3 trigonal pyramid, and edges with two equivalent O(1)TiFe3 trigonal pyramids. In the fifth O site, O(5) is bonded to one Ti(1), one Fe(2), and two equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OTiFe3 trigonal pyramids. In the sixth O site, O(6) is bonded to one Ti(1), one Fe(2), one Fe(3), and one Fe(4) atom to form OTiFe3 trigonal pyramids that share  a cornercorner with one O(1)TiFe3 trigonal pyramid, corners with two equivalent O(8)Ti2Fe2 trigonal pyramids, corners with two equivalent O(3)TiFe3 trigonal pyramids, corners with three equivalent O(4)TiFe3 trigonal pyramids, corners with three equivalent O(7)TiFe3 trigonal pyramids,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(1)TiFe3 trigonal pyramid, and  an edgeedge with one O(5)TiFe3 trigonal pyramid. In the seventh O site, O(7) is bonded to one Ti(2), one Fe(2), and two equivalent Fe(4) atoms to form distorted OTiFe3 trigonal pyramids that share  a cornercorner with one O(1)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid,  a cornercorner with one O(5)TiFe3 trigonal pyramid, corners with two equivalent O(9)Ti2Fe2 trigonal pyramids, corners with three equivalent O(6)TiFe3 trigonal pyramids, corners with four equivalent O(8)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(8)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(3)TiFe3 trigonal pyramid, and  an edgeedge with one O(7)TiFe3 trigonal pyramid. In the eighth O site, O(8) is bonded to two equivalent Ti(2) and two equivalent Fe(4) atoms to form distorted OTi2Fe2 trigonal pyramids that share corners with two equivalent O(3)TiFe3 trigonal pyramids, corners with two equivalent O(6)TiFe3 trigonal pyramids, corners with four equivalent O(9)Ti2Fe2 trigonal pyramids, corners with four equivalent O(7)TiFe3 trigonal pyramids,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(7)TiFe3 trigonal pyramid, and edges with two equivalent O(8)Ti2Fe2 trigonal pyramids. In the ninth O site, O(9) is bonded to two equivalent Ti(2), one Fe(3), and one Fe(4) atom to form distorted OTi2Fe2 trigonal pyramids that share  a cornercorner with one O(1)TiFe3 trigonal pyramid,  a cornercorner with one O(4)TiFe3 trigonal pyramid, corners with two equivalent O(7)TiFe3 trigonal pyramids, corners with three equivalent O(3)TiFe3 trigonal pyramids, corners with four equivalent O(8)Ti2Fe2 trigonal pyramids,  an edgeedge with one O(8)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(9)Ti2Fe2 trigonal pyramid,  an edgeedge with one O(6)TiFe3 trigonal pyramid, and  an edgeedge with one O(7)TiFe3 trigonal pyramid. is represented by the CIF file [CIF]
data_Ti2Fe4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.145
_cell_length_b   5.516
_cell_length_c   11.665
_cell_angle_alpha   97.412
_cell_angle_beta   102.653
_cell_angle_gamma   91.138
_symmetry_Int_Tables_number   1
_cell_volume   319.930
_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  0.048  0.334  0.097  1.0
  Ti  Ti1  1  0.720  0.010  0.427  1.0
  Ti  Ti2  1  0.280  0.990  0.573  1.0
  Ti  Ti3  1  0.952  0.666  0.903  1.0
  Fe  Fe4  1  0.550  0.842  0.096  1.0
  Fe  Fe5  1  0.618  0.332  0.236  1.0
  Fe  Fe6  1  0.122  0.817  0.236  1.0
  Fe  Fe7  1  0.779  0.489  0.568  1.0
  Fe  Fe8  1  0.221  0.511  0.432  1.0
  Fe  Fe9  1  0.878  0.183  0.764  1.0
  Fe  Fe10  1  0.382  0.668  0.764  1.0
  Fe  Fe11  1  0.450  0.158  0.904  1.0
  O  O12  1  0.379  0.577  0.167  1.0
  O  O13  1  0.899  0.683  0.059  1.0
  O  O14  1  0.790  0.973  0.274  1.0
  O  O15  1  0.262  0.092  0.167  1.0
  O  O16  1  0.699  0.191  0.070  1.0
  O  O17  1  0.977  0.486  0.262  1.0
  O  O18  1  0.560  0.336  0.396  1.0
  O  O19  1  0.939  0.770  0.498  1.0
  O  O20  1  0.366  0.859  0.398  1.0
  O  O21  1  0.634  0.141  0.602  1.0
  O  O22  1  0.061  0.230  0.502  1.0
  O  O23  1  0.440  0.664  0.604  1.0
  O  O24  1  0.023  0.514  0.738  1.0
  O  O25  1  0.301  0.809  0.930  1.0
  O  O26  1  0.738  0.908  0.833  1.0
  O  O27  1  0.210  0.027  0.726  1.0
  O  O28  1  0.101  0.317  0.941  1.0
  O  O29  1  0.621  0.423  0.833  1.0
[/CIF]
.