The structure described by CaFe2O4 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-20°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Fe(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(2)CaFe3 trigonal pyramid. In the second O site, O(2) is bonded to one Ca(2), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(1)CaFe3 trigonal pyramid. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(3)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(4)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(4)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids. is represented by the CIF file [CIF]
data_Ca(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.140
_cell_length_b   5.960
_cell_length_c   11.084
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   339.559
_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  0.856  0.248  0.750  1.0
  Ca  Ca1  1  0.144  0.748  0.250  1.0
  Ca  Ca2  1  0.530  0.249  0.250  1.0
  Ca  Ca3  1  0.470  0.748  0.750  1.0
  Fe  Fe4  1  0.497  0.256  0.518  1.0
  Fe  Fe5  1  0.497  0.256  0.982  1.0
  Fe  Fe6  1  0.999  0.502  0.499  1.0
  Fe  Fe7  1  0.999  0.502  0.001  1.0
  Fe  Fe8  1  0.503  0.756  0.482  1.0
  Fe  Fe9  1  0.503  0.756  0.018  1.0
  Fe  Fe10  1  0.001  0.002  1.000  1.0
  Fe  Fe11  1  0.001  0.002  0.500  1.0
  O  O12  1  0.839  0.747  0.403  1.0
  O  O13  1  0.839  0.747  0.097  1.0
  O  O14  1  0.161  0.247  0.597  1.0
  O  O15  1  0.161  0.247  0.903  1.0
  O  O16  1  0.181  0.749  0.588  1.0
  O  O17  1  0.181  0.749  0.912  1.0
  O  O18  1  0.819  0.249  0.412  1.0
  O  O19  1  0.819  0.249  0.088  1.0
  O  O20  1  0.667  0.501  0.606  1.0
  O  O21  1  0.665  0.998  0.897  1.0
  O  O22  1  0.333  0.001  0.394  1.0
  O  O23  1  0.335  0.498  0.103  1.0
  O  O24  1  0.335  0.498  0.397  1.0
  O  O25  1  0.333  0.001  0.106  1.0
  O  O26  1  0.665  0.998  0.603  1.0
  O  O27  1  0.667  0.501  0.894  1.0
[/CIF]
.
The structure described by CaFe2O4 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-20°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Fe(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(2)CaFe3 trigonal pyramid. In the second O site, O(2) is bonded to one Ca(2), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(1)CaFe3 trigonal pyramid. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(3)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(4)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(4)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids. is represented by the CIF file [CIF]
data_Ca(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.140
_cell_length_b   5.960
_cell_length_c   11.084
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   339.559
_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  0.856  0.248  0.750  1.0
  Ca  Ca1  1  0.144  0.748  0.250  1.0
  Ca  Ca2  1  0.530  0.249  0.250  1.0
  Ca  Ca3  1  0.470  0.748  0.750  1.0
  Fe  Fe4  1  0.497  0.256  0.518  1.0
  Fe  Fe5  1  0.497  0.256  0.982  1.0
  Fe  Fe6  1  0.999  0.502  0.499  1.0
  Fe  Fe7  1  0.999  0.502  0.001  1.0
  Fe  Fe8  1  0.503  0.756  0.482  1.0
  Fe  Fe9  1  0.503  0.756  0.018  1.0
  Fe  Fe10  1  0.001  0.002  1.000  1.0
  Fe  Fe11  1  0.001  0.002  0.500  1.0
  O  O12  1  0.839  0.747  0.403  1.0
  O  O13  1  0.839  0.747  0.097  1.0
  O  O14  1  0.161  0.247  0.597  1.0
  O  O15  1  0.161  0.247  0.903  1.0
  O  O16  1  0.181  0.749  0.588  1.0
  O  O17  1  0.181  0.749  0.912  1.0
  O  O18  1  0.819  0.249  0.412  1.0
  O  O19  1  0.819  0.249  0.088  1.0
  O  O20  1  0.667  0.501  0.606  1.0
  O  O21  1  0.665  0.998  0.897  1.0
  O  O22  1  0.333  0.001  0.394  1.0
  O  O23  1  0.335  0.498  0.103  1.0
  O  O24  1  0.335  0.498  0.397  1.0
  O  O25  1  0.333  0.001  0.106  1.0
  O  O26  1  0.665  0.998  0.603  1.0
  O  O27  1  0.667  0.501  0.894  1.0
[/CIF]
.