The compound described by CaFe2O4 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Fe(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 0-45°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and three equivalent Fe(1) atoms to form distorted OCa2Fe3 trigonal bipyramids that share corners with four equivalent O(3)Ca2Fe4 octahedra, corners with five equivalent O(2)Ca2Fe2 tetrahedra, corners with two equivalent O(1)Ca2Fe3 trigonal bipyramids, edges with three equivalent O(3)Ca2Fe4 octahedra,  an edgeedge with one O(2)Ca2Fe2 tetrahedra, and edges with five equivalent O(1)Ca2Fe3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 9-42°. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Fe(1) atoms to form distorted OCa2Fe2 tetrahedra that share corners with two equivalent O(2)Ca2Fe2 tetrahedra, corners with ten equivalent O(1)Ca2Fe3 trigonal bipyramids, edges with four equivalent O(3)Ca2Fe4 octahedra, and edges with two equivalent O(1)Ca2Fe3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and four equivalent Fe(1) atoms to form distorted OCa2Fe4 octahedra that share corners with two equivalent O(3)Ca2Fe4 octahedra, corners with eight equivalent O(1)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(3)Ca2Fe4 octahedra, edges with four equivalent O(2)Ca2Fe2 tetrahedra, and edges with six equivalent O(1)Ca2Fe3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 47°. is represented by the CIF file [CIF]
data_Ca(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.239
_cell_length_b   5.239
_cell_length_c   10.137
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   145.976
_symmetry_Int_Tables_number   1
_cell_volume   155.657
_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  0.610  0.390  0.750  1.0
  Ca  Ca1  1  0.390  0.610  0.250  1.0
  Fe  Fe2  1  0.135  0.865  0.071  1.0
  Fe  Fe3  1  0.865  0.135  0.929  1.0
  Fe  Fe4  1  0.135  0.865  0.429  1.0
  Fe  Fe5  1  0.865  0.135  0.571  1.0
  O  O6  1  0.769  0.231  0.392  1.0
  O  O7  1  0.231  0.769  0.608  1.0
  O  O8  1  0.231  0.769  0.892  1.0
  O  O9  1  0.769  0.231  0.108  1.0
  O  O10  1  0.060  0.940  0.250  1.0
  O  O11  1  0.940  0.060  0.750  1.0
  O  O12  1  0.500  0.500  0.000  1.0
  O  O13  1  0.500  0.500  0.500  1.0
[/CIF]
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The compound described by CaFe2O4 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Fe(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 0-45°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and three equivalent Fe(1) atoms to form distorted OCa2Fe3 trigonal bipyramids that share corners with four equivalent O(3)Ca2Fe4 octahedra, corners with five equivalent O(2)Ca2Fe2 tetrahedra, corners with two equivalent O(1)Ca2Fe3 trigonal bipyramids, edges with three equivalent O(3)Ca2Fe4 octahedra,  an edgeedge with one O(2)Ca2Fe2 tetrahedra, and edges with five equivalent O(1)Ca2Fe3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 9-42°. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Fe(1) atoms to form distorted OCa2Fe2 tetrahedra that share corners with two equivalent O(2)Ca2Fe2 tetrahedra, corners with ten equivalent O(1)Ca2Fe3 trigonal bipyramids, edges with four equivalent O(3)Ca2Fe4 octahedra, and edges with two equivalent O(1)Ca2Fe3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and four equivalent Fe(1) atoms to form distorted OCa2Fe4 octahedra that share corners with two equivalent O(3)Ca2Fe4 octahedra, corners with eight equivalent O(1)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(3)Ca2Fe4 octahedra, edges with four equivalent O(2)Ca2Fe2 tetrahedra, and edges with six equivalent O(1)Ca2Fe3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 47°. is represented by the CIF file [CIF]
data_Ca(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.239
_cell_length_b   5.239
_cell_length_c   10.137
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   145.976
_symmetry_Int_Tables_number   1
_cell_volume   155.657
_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  0.610  0.390  0.750  1.0
  Ca  Ca1  1  0.390  0.610  0.250  1.0
  Fe  Fe2  1  0.135  0.865  0.071  1.0
  Fe  Fe3  1  0.865  0.135  0.929  1.0
  Fe  Fe4  1  0.135  0.865  0.429  1.0
  Fe  Fe5  1  0.865  0.135  0.571  1.0
  O  O6  1  0.769  0.231  0.392  1.0
  O  O7  1  0.231  0.769  0.608  1.0
  O  O8  1  0.231  0.769  0.892  1.0
  O  O9  1  0.769  0.231  0.108  1.0
  O  O10  1  0.060  0.940  0.250  1.0
  O  O11  1  0.940  0.060  0.750  1.0
  O  O12  1  0.500  0.500  0.000  1.0
  O  O13  1  0.500  0.500  0.500  1.0
[/CIF]
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