The material described by FeCrO4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 20-62°. In the second Cr site, Cr(2) is bonded to two equivalent O(3) and two equivalent O(5) atoms to form CrO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-57°. 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(5) atoms to form FeO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra, corners with four equivalent Cr(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent Cr(2)O4 tetrahedra, corners with four equivalent Cr(1)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Cr(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted edge-sharing OCrFe3 tetrahedra. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Cr(2) and one Fe(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Cr(2), one Fe(1), and one Fe(2) atom. is represented by the CIF file [CIF]
data_CrFeO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.792
_cell_length_b   6.792
_cell_length_c   6.834
_cell_angle_alpha   78.011
_cell_angle_beta   78.011
_cell_angle_gamma   84.831
_symmetry_Int_Tables_number   1
_cell_volume   301.273
_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
  Cr  Cr0  1  0.720  0.720  0.412  1.0
  Cr  Cr1  1  0.742  0.258  0.000  1.0
  Cr  Cr2  1  0.258  0.742  0.000  1.0
  Cr  Cr3  1  0.280  0.280  0.588  1.0
  Fe  Fe4  1  0.796  0.796  0.870  1.0
  Fe  Fe5  1  0.817  0.183  0.500  1.0
  Fe  Fe6  1  0.183  0.817  0.500  1.0
  Fe  Fe7  1  0.204  0.204  0.130  1.0
  O  O8  1  0.858  0.858  0.543  1.0
  O  O9  1  0.791  0.791  0.151  1.0
  O  O10  1  0.793  0.498  0.890  1.0
  O  O11  1  0.498  0.793  0.890  1.0
  O  O12  1  0.477  0.797  0.477  1.0
  O  O13  1  0.797  0.477  0.477  1.0
  O  O14  1  0.107  0.798  0.804  1.0
  O  O15  1  0.798  0.107  0.804  1.0
  O  O16  1  0.893  0.202  0.196  1.0
  O  O17  1  0.202  0.893  0.196  1.0
  O  O18  1  0.523  0.203  0.523  1.0
  O  O19  1  0.203  0.523  0.523  1.0
  O  O20  1  0.502  0.207  0.110  1.0
  O  O21  1  0.207  0.502  0.110  1.0
  O  O22  1  0.209  0.209  0.849  1.0
  O  O23  1  0.142  0.142  0.457  1.0
[/CIF]
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The material described by FeCrO4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 20-62°. In the second Cr site, Cr(2) is bonded to two equivalent O(3) and two equivalent O(5) atoms to form CrO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-57°. 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(5) atoms to form FeO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra, corners with four equivalent Cr(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent Cr(2)O4 tetrahedra, corners with four equivalent Cr(1)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Cr(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted edge-sharing OCrFe3 tetrahedra. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Cr(2) and one Fe(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Cr(2), one Fe(1), and one Fe(2) atom. is represented by the CIF file [CIF]
data_CrFeO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.792
_cell_length_b   6.792
_cell_length_c   6.834
_cell_angle_alpha   78.011
_cell_angle_beta   78.011
_cell_angle_gamma   84.831
_symmetry_Int_Tables_number   1
_cell_volume   301.273
_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
  Cr  Cr0  1  0.720  0.720  0.412  1.0
  Cr  Cr1  1  0.742  0.258  0.000  1.0
  Cr  Cr2  1  0.258  0.742  0.000  1.0
  Cr  Cr3  1  0.280  0.280  0.588  1.0
  Fe  Fe4  1  0.796  0.796  0.870  1.0
  Fe  Fe5  1  0.817  0.183  0.500  1.0
  Fe  Fe6  1  0.183  0.817  0.500  1.0
  Fe  Fe7  1  0.204  0.204  0.130  1.0
  O  O8  1  0.858  0.858  0.543  1.0
  O  O9  1  0.791  0.791  0.151  1.0
  O  O10  1  0.793  0.498  0.890  1.0
  O  O11  1  0.498  0.793  0.890  1.0
  O  O12  1  0.477  0.797  0.477  1.0
  O  O13  1  0.797  0.477  0.477  1.0
  O  O14  1  0.107  0.798  0.804  1.0
  O  O15  1  0.798  0.107  0.804  1.0
  O  O16  1  0.893  0.202  0.196  1.0
  O  O17  1  0.202  0.893  0.196  1.0
  O  O18  1  0.523  0.203  0.523  1.0
  O  O19  1  0.203  0.523  0.523  1.0
  O  O20  1  0.502  0.207  0.110  1.0
  O  O21  1  0.207  0.502  0.110  1.0
  O  O22  1  0.209  0.209  0.849  1.0
  O  O23  1  0.142  0.142  0.457  1.0
[/CIF]
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