The structure described by Ca2Fe2O5 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 8-16°. In the second Fe site, Fe(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form FeO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and  an edgeedge with one Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Fe(1) atoms to form distorted OCa4Fe2 octahedra that share corners with two equivalent O(1)Ca4Fe2 octahedra, corners with four equivalent O(4)Ca2Fe2 trigonal pyramids, edges with two equivalent O(1)Ca4Fe2 octahedra, and faces with four equivalent O(2)Ca4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to four equivalent Ca(1) and two equivalent Fe(1) atoms to form distorted OCa4Fe2 octahedra that share corners with two equivalent O(2)Ca4Fe2 octahedra, corners with four equivalent O(4)Ca2Fe2 trigonal pyramids, edges with two equivalent O(2)Ca4Fe2 octahedra, and faces with four equivalent O(1)Ca4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Fe(2) atoms to form OCa2Fe2 trigonal pyramids that share corners with four equivalent O(1)Ca4Fe2 octahedra, corners with four equivalent O(2)Ca4Fe2 octahedra, and  an edgeedge with one O(4)Ca2Fe2 trigonal pyramid. The corner-sharing octahedral tilt angles range from 22-81°. is represented by the CIF card [CIF]
data_Ca2Fe2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.565
_cell_length_b   5.658
_cell_length_c   8.397
_cell_angle_alpha   109.367
_cell_angle_beta   109.027
_cell_angle_gamma   90.908
_symmetry_Int_Tables_number   1
_cell_volume   233.510
_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
  Ca  Ca0  1  0.419  0.365  0.287  1.0
  Ca  Ca1  1  0.581  0.635  0.713  1.0
  Ca  Ca2  1  0.868  0.922  0.287  1.0
  Ca  Ca3  1  0.132  0.078  0.713  1.0
  Fe  Fe4  1  0.500  0.000  0.500  1.0
  Fe  Fe5  1  0.000  0.500  0.500  1.0
  Fe  Fe6  1  0.175  0.691  0.000  1.0
  Fe  Fe7  1  0.825  0.309  0.000  1.0
  O  O8  1  0.232  0.732  0.463  1.0
  O  O9  1  0.260  0.260  0.520  1.0
  O  O10  1  0.740  0.740  0.480  1.0
  O  O11  1  0.768  0.268  0.537  1.0
  O  O12  1  0.389  0.926  0.219  1.0
  O  O13  1  0.611  0.074  0.781  1.0
  O  O14  1  0.830  0.293  0.219  1.0
  O  O15  1  0.170  0.707  0.781  1.0
  O  O16  1  0.181  0.343  0.000  1.0
  O  O17  1  0.819  0.657  0.000  1.0
[/CIF]
.
The structure described by Ca2Fe2O5 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 8-16°. In the second Fe site, Fe(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form FeO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and  an edgeedge with one Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Fe(1) atoms to form distorted OCa4Fe2 octahedra that share corners with two equivalent O(1)Ca4Fe2 octahedra, corners with four equivalent O(4)Ca2Fe2 trigonal pyramids, edges with two equivalent O(1)Ca4Fe2 octahedra, and faces with four equivalent O(2)Ca4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to four equivalent Ca(1) and two equivalent Fe(1) atoms to form distorted OCa4Fe2 octahedra that share corners with two equivalent O(2)Ca4Fe2 octahedra, corners with four equivalent O(4)Ca2Fe2 trigonal pyramids, edges with two equivalent O(2)Ca4Fe2 octahedra, and faces with four equivalent O(1)Ca4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Fe(2) atoms to form OCa2Fe2 trigonal pyramids that share corners with four equivalent O(1)Ca4Fe2 octahedra, corners with four equivalent O(2)Ca4Fe2 octahedra, and  an edgeedge with one O(4)Ca2Fe2 trigonal pyramid. The corner-sharing octahedral tilt angles range from 22-81°. is represented by the CIF card [CIF]
data_Ca2Fe2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.565
_cell_length_b   5.658
_cell_length_c   8.397
_cell_angle_alpha   109.367
_cell_angle_beta   109.027
_cell_angle_gamma   90.908
_symmetry_Int_Tables_number   1
_cell_volume   233.510
_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
  Ca  Ca0  1  0.419  0.365  0.287  1.0
  Ca  Ca1  1  0.581  0.635  0.713  1.0
  Ca  Ca2  1  0.868  0.922  0.287  1.0
  Ca  Ca3  1  0.132  0.078  0.713  1.0
  Fe  Fe4  1  0.500  0.000  0.500  1.0
  Fe  Fe5  1  0.000  0.500  0.500  1.0
  Fe  Fe6  1  0.175  0.691  0.000  1.0
  Fe  Fe7  1  0.825  0.309  0.000  1.0
  O  O8  1  0.232  0.732  0.463  1.0
  O  O9  1  0.260  0.260  0.520  1.0
  O  O10  1  0.740  0.740  0.480  1.0
  O  O11  1  0.768  0.268  0.537  1.0
  O  O12  1  0.389  0.926  0.219  1.0
  O  O13  1  0.611  0.074  0.781  1.0
  O  O14  1  0.830  0.293  0.219  1.0
  O  O15  1  0.170  0.707  0.781  1.0
  O  O16  1  0.181  0.343  0.000  1.0
  O  O17  1  0.819  0.657  0.000  1.0
[/CIF]
.