The compound described by CaFe3O7 crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted CaO7 pentagonal bipyramids that share  a cornercorner with one Fe(2)O5 trigonal bipyramid, corners with six equivalent Fe(1)O5 trigonal bipyramids, edges with two equivalent Fe(1)O5 trigonal bipyramids, and edges with two equivalent Fe(2)O5 trigonal bipyramids. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO5 trigonal bipyramids that share corners with three equivalent Ca(1)O7 pentagonal bipyramids, corners with two equivalent Fe(2)O5 trigonal bipyramids,  an edgeedge with one Ca(1)O7 pentagonal bipyramid,  an edgeedge with one Fe(2)O5 trigonal bipyramid, and edges with two equivalent Fe(1)O5 trigonal bipyramids. In the second Fe site, Fe(2) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Ca(1)O7 pentagonal bipyramid, corners with four equivalent Fe(1)O5 trigonal bipyramids, edges with two equivalent Ca(1)O7 pentagonal bipyramids, and edges with two equivalent Fe(1)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Ca(1) and one Fe(2) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Fe(1) atom. In the third O site, O(1) is bonded to one Ca(1), one Fe(2), and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing OCaFe3 tetrahedra. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Fe(2), and two equivalent Fe(1) atoms. is represented by the CIF file [CIF]
data_CaFe3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.332
_cell_length_b   10.485
_cell_length_c   11.217
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   627.029
_cell_formula_units_Z   4
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
  Ca  Ca0  1  0.686  0.750  0.082  1.0
  Ca  Ca1  1  0.186  0.250  0.418  1.0
  Ca  Ca2  1  0.314  0.250  0.918  1.0
  Ca  Ca3  1  0.814  0.750  0.582  1.0
  Fe  Fe4  1  0.305  0.024  0.690  1.0
  Fe  Fe5  1  0.805  0.976  0.810  1.0
  Fe  Fe6  1  0.695  0.524  0.310  1.0
  Fe  Fe7  1  0.195  0.476  0.190  1.0
  Fe  Fe8  1  0.313  0.750  0.784  1.0
  Fe  Fe9  1  0.813  0.250  0.716  1.0
  Fe  Fe10  1  0.687  0.250  0.216  1.0
  Fe  Fe11  1  0.187  0.750  0.284  1.0
  Fe  Fe12  1  0.805  0.524  0.810  1.0
  Fe  Fe13  1  0.305  0.476  0.690  1.0
  Fe  Fe14  1  0.195  0.024  0.190  1.0
  Fe  Fe15  1  0.695  0.976  0.310  1.0
  O  O16  1  0.932  0.121  0.275  1.0
  O  O17  1  0.432  0.879  0.225  1.0
  O  O18  1  0.068  0.621  0.725  1.0
  O  O19  1  0.568  0.379  0.775  1.0
  O  O20  1  0.068  0.879  0.725  1.0
  O  O21  1  0.568  0.121  0.775  1.0
  O  O22  1  0.932  0.379  0.275  1.0
  O  O23  1  0.432  0.621  0.225  1.0
  O  O24  1  0.453  0.119  0.282  1.0
  O  O25  1  0.953  0.881  0.218  1.0
  O  O26  1  0.547  0.619  0.718  1.0
  O  O27  1  0.047  0.381  0.782  1.0
  O  O28  1  0.547  0.881  0.718  1.0
  O  O29  1  0.047  0.119  0.782  1.0
  O  O30  1  0.453  0.381  0.282  1.0
  O  O31  1  0.953  0.619  0.218  1.0
  O  O32  1  0.136  0.750  0.442  1.0
  O  O33  1  0.636  0.250  0.058  1.0
  O  O34  1  0.864  0.250  0.558  1.0
  O  O35  1  0.364  0.750  0.942  1.0
  O  O36  1  0.220  0.418  0.042  1.0
  O  O37  1  0.720  0.582  0.458  1.0
  O  O38  1  0.780  0.918  0.958  1.0
  O  O39  1  0.280  0.082  0.542  1.0
  O  O40  1  0.780  0.582  0.958  1.0
  O  O41  1  0.280  0.418  0.542  1.0
  O  O42  1  0.220  0.082  0.042  1.0
  O  O43  1  0.720  0.918  0.458  1.0
[/CIF]
.
The compound described by CaFe3O7 crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted CaO7 pentagonal bipyramids that share  a cornercorner with one Fe(2)O5 trigonal bipyramid, corners with six equivalent Fe(1)O5 trigonal bipyramids, edges with two equivalent Fe(1)O5 trigonal bipyramids, and edges with two equivalent Fe(2)O5 trigonal bipyramids. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO5 trigonal bipyramids that share corners with three equivalent Ca(1)O7 pentagonal bipyramids, corners with two equivalent Fe(2)O5 trigonal bipyramids,  an edgeedge with one Ca(1)O7 pentagonal bipyramid,  an edgeedge with one Fe(2)O5 trigonal bipyramid, and edges with two equivalent Fe(1)O5 trigonal bipyramids. In the second Fe site, Fe(2) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Ca(1)O7 pentagonal bipyramid, corners with four equivalent Fe(1)O5 trigonal bipyramids, edges with two equivalent Ca(1)O7 pentagonal bipyramids, and edges with two equivalent Fe(1)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Ca(1) and one Fe(2) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Fe(1) atom. In the third O site, O(1) is bonded to one Ca(1), one Fe(2), and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing OCaFe3 tetrahedra. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Fe(2), and two equivalent Fe(1) atoms. is represented by the CIF file [CIF]
data_CaFe3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.332
_cell_length_b   10.485
_cell_length_c   11.217
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   627.029
_cell_formula_units_Z   4
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
  Ca  Ca0  1  0.686  0.750  0.082  1.0
  Ca  Ca1  1  0.186  0.250  0.418  1.0
  Ca  Ca2  1  0.314  0.250  0.918  1.0
  Ca  Ca3  1  0.814  0.750  0.582  1.0
  Fe  Fe4  1  0.305  0.024  0.690  1.0
  Fe  Fe5  1  0.805  0.976  0.810  1.0
  Fe  Fe6  1  0.695  0.524  0.310  1.0
  Fe  Fe7  1  0.195  0.476  0.190  1.0
  Fe  Fe8  1  0.313  0.750  0.784  1.0
  Fe  Fe9  1  0.813  0.250  0.716  1.0
  Fe  Fe10  1  0.687  0.250  0.216  1.0
  Fe  Fe11  1  0.187  0.750  0.284  1.0
  Fe  Fe12  1  0.805  0.524  0.810  1.0
  Fe  Fe13  1  0.305  0.476  0.690  1.0
  Fe  Fe14  1  0.195  0.024  0.190  1.0
  Fe  Fe15  1  0.695  0.976  0.310  1.0
  O  O16  1  0.932  0.121  0.275  1.0
  O  O17  1  0.432  0.879  0.225  1.0
  O  O18  1  0.068  0.621  0.725  1.0
  O  O19  1  0.568  0.379  0.775  1.0
  O  O20  1  0.068  0.879  0.725  1.0
  O  O21  1  0.568  0.121  0.775  1.0
  O  O22  1  0.932  0.379  0.275  1.0
  O  O23  1  0.432  0.621  0.225  1.0
  O  O24  1  0.453  0.119  0.282  1.0
  O  O25  1  0.953  0.881  0.218  1.0
  O  O26  1  0.547  0.619  0.718  1.0
  O  O27  1  0.047  0.381  0.782  1.0
  O  O28  1  0.547  0.881  0.718  1.0
  O  O29  1  0.047  0.119  0.782  1.0
  O  O30  1  0.453  0.381  0.282  1.0
  O  O31  1  0.953  0.619  0.218  1.0
  O  O32  1  0.136  0.750  0.442  1.0
  O  O33  1  0.636  0.250  0.058  1.0
  O  O34  1  0.864  0.250  0.558  1.0
  O  O35  1  0.364  0.750  0.942  1.0
  O  O36  1  0.220  0.418  0.042  1.0
  O  O37  1  0.720  0.582  0.458  1.0
  O  O38  1  0.780  0.918  0.958  1.0
  O  O39  1  0.280  0.082  0.542  1.0
  O  O40  1  0.780  0.582  0.958  1.0
  O  O41  1  0.280  0.418  0.542  1.0
  O  O42  1  0.220  0.082  0.042  1.0
  O  O43  1  0.720  0.918  0.458  1.0
[/CIF]
.