The compound described by FeCr2O4 is Spinel structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with four equivalent Cr(3)O6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with four equivalent Cr(3)O6 octahedra. In the third Cr site, Cr(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with two equivalent Cr(3)O6 octahedra. Fe(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form FeO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Cr(2)O6 octahedra, and corners with six equivalent Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(3), and one Fe(1) atom. In the second O site, O(2) is bonded to one Cr(1), one Cr(2), one Cr(3), and one Fe(1) atom to form a mixture of distorted corner and edge-sharing OCr3Fe trigonal pyramids. In the third O site, O(3) is bonded to one Cr(2), two equivalent Cr(3), and one Fe(1) atom to form a mixture of distorted corner and edge-sharing OCr3Fe trigonal pyramids. is represented by the CIF card [CIF]
data_Cr2FeO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.033
_cell_length_b   5.992
_cell_length_c   6.040
_cell_angle_alpha   60.621
_cell_angle_beta   60.702
_cell_angle_gamma   91.268
_symmetry_Int_Tables_number   1
_cell_volume   155.749
_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
  Cr  Cr0  1  1.000  1.000  0.500  1.0
  Cr  Cr1  1  0.000  0.500  1.000  1.0
  Cr  Cr2  1  0.000  0.500  0.500  1.0
  Cr  Cr3  1  0.500  0.500  0.000  1.0
  Fe  Fe4  1  0.625  0.875  0.250  1.0
  Fe  Fe5  1  0.375  0.125  0.750  1.0
  O  O6  1  0.759  0.730  0.529  1.0
  O  O7  1  0.232  0.260  0.027  1.0
  O  O8  1  0.787  0.260  0.472  1.0
  O  O9  1  0.760  0.289  0.971  1.0
  O  O10  1  0.241  0.270  0.471  1.0
  O  O11  1  0.768  0.740  0.973  1.0
  O  O12  1  0.213  0.740  0.528  1.0
  O  O13  1  0.240  0.711  0.029  1.0
[/CIF]
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The compound described by FeCr2O4 is Spinel structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with four equivalent Cr(3)O6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with four equivalent Cr(3)O6 octahedra. In the third Cr site, Cr(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with two equivalent Cr(3)O6 octahedra. Fe(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form FeO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Cr(2)O6 octahedra, and corners with six equivalent Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(3), and one Fe(1) atom. In the second O site, O(2) is bonded to one Cr(1), one Cr(2), one Cr(3), and one Fe(1) atom to form a mixture of distorted corner and edge-sharing OCr3Fe trigonal pyramids. In the third O site, O(3) is bonded to one Cr(2), two equivalent Cr(3), and one Fe(1) atom to form a mixture of distorted corner and edge-sharing OCr3Fe trigonal pyramids. is represented by the CIF card [CIF]
data_Cr2FeO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.033
_cell_length_b   5.992
_cell_length_c   6.040
_cell_angle_alpha   60.621
_cell_angle_beta   60.702
_cell_angle_gamma   91.268
_symmetry_Int_Tables_number   1
_cell_volume   155.749
_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
  Cr  Cr0  1  1.000  1.000  0.500  1.0
  Cr  Cr1  1  0.000  0.500  1.000  1.0
  Cr  Cr2  1  0.000  0.500  0.500  1.0
  Cr  Cr3  1  0.500  0.500  0.000  1.0
  Fe  Fe4  1  0.625  0.875  0.250  1.0
  Fe  Fe5  1  0.375  0.125  0.750  1.0
  O  O6  1  0.759  0.730  0.529  1.0
  O  O7  1  0.232  0.260  0.027  1.0
  O  O8  1  0.787  0.260  0.472  1.0
  O  O9  1  0.760  0.289  0.971  1.0
  O  O10  1  0.241  0.270  0.471  1.0
  O  O11  1  0.768  0.740  0.973  1.0
  O  O12  1  0.213  0.740  0.528  1.0
  O  O13  1  0.240  0.711  0.029  1.0
[/CIF]
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