The material described by MgFeO2 crystallizes in the triclinic P1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(6), two equivalent O(4), and two equivalent O(7) atoms. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one O(4), one O(8), two equivalent O(1), and two equivalent O(5) atoms. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to one O(8), two equivalent O(3), and two equivalent O(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 5-coordinate geometry to one O(6), two equivalent O(2), and two equivalent O(5) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(5), and two equivalent O(4) atoms. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(3), and two equivalent O(6) atoms. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(8) atoms. In the fourth Fe site, Fe(4) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(7), and two equivalent O(1) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mg(2), one Fe(3), and two equivalent Fe(4) atoms to form distorted OMg3Fe3 octahedra that share corners with two equivalent O(5)Mg4Fe square pyramids,  a cornercorner with one O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(1)Mg3Fe3 octahedra, edges with two equivalent O(4)Mg3Fe3 octahedra,  an edgeedge with one O(5)Mg4Fe square pyramid, edges with two equivalent O(7)Mg4Fe square pyramids, and edges with two equivalent O(8)Mg2Fe2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Mg(4), one Fe(1), and two equivalent Fe(3) atoms to form distorted OMg2Fe3 trigonal bipyramids that share corners with two equivalent O(1)Mg3Fe3 octahedra, corners with two equivalent O(4)Mg3Fe3 octahedra, corners with two equivalent O(5)Mg4Fe square pyramids, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra,  an edgeedge with one O(8)Mg2Fe2 tetrahedra, edges with two equivalent O(2)Mg2Fe3 trigonal bipyramids, and  a faceface with one O(5)Mg4Fe square pyramid. The corner-sharing octahedral tilt angles range from 44-68°. In the third O site, O(3) is bonded to two equivalent Mg(3), one Fe(4), and two equivalent Fe(2) atoms to form distorted OMg2Fe3 trigonal bipyramids that share corners with two equivalent O(1)Mg3Fe3 octahedra, corners with two equivalent O(4)Mg3Fe3 octahedra, corners with two equivalent O(7)Mg4Fe square pyramids, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra,  an edgeedge with one O(6)Mg2Fe2 tetrahedra, edges with two equivalent O(3)Mg2Fe3 trigonal bipyramids, and  a faceface with one O(7)Mg4Fe square pyramid. The corner-sharing octahedral tilt angles range from 44-68°. In the fourth O site, O(4) is bonded to one Mg(2), two equivalent Mg(1), one Fe(2), and two equivalent Fe(1) atoms to form distorted OMg3Fe3 octahedra that share corners with two equivalent O(7)Mg4Fe square pyramids,  a cornercorner with one O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(1)Mg3Fe3 octahedra, edges with two equivalent O(4)Mg3Fe3 octahedra,  an edgeedge with one O(7)Mg4Fe square pyramid, edges with two equivalent O(5)Mg4Fe square pyramids, and edges with two equivalent O(6)Mg2Fe2 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Mg(2), two equivalent Mg(4), and one Fe(1) atom to form OMg4Fe square pyramids that share corners with two equivalent O(1)Mg3Fe3 octahedra, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids,  an edgeedge with one O(1)Mg3Fe3 octahedra, edges with two equivalent O(4)Mg3Fe3 octahedra, edges with two equivalent O(5)Mg4Fe square pyramids, and  a faceface with one O(2)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 15-16°. In the sixth O site, O(6) is bonded to one Mg(1), one Mg(4), and two equivalent Fe(2) atoms to form OMg2Fe2 tetrahedra that share  a cornercorner with one O(1)Mg3Fe3 octahedra, corners with two equivalent O(5)Mg4Fe square pyramids, corners with two equivalent O(7)Mg4Fe square pyramids, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(4)Mg3Fe3 octahedra, and  an edgeedge with one O(3)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. In the seventh O site, O(7) is bonded to two equivalent Mg(1), two equivalent Mg(3), and one Fe(4) atom to form OMg4Fe square pyramids that share corners with two equivalent O(4)Mg3Fe3 octahedra, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids,  an edgeedge with one O(4)Mg3Fe3 octahedra, edges with two equivalent O(1)Mg3Fe3 octahedra, edges with two equivalent O(7)Mg4Fe square pyramids, and  a faceface with one O(3)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 15°. In the eighth O site, O(8) is bonded to one Mg(2), one Mg(3), and two equivalent Fe(3) atoms to form OMg2Fe2 tetrahedra that share  a cornercorner with one O(4)Mg3Fe3 octahedra, corners with two equivalent O(5)Mg4Fe square pyramids, corners with two equivalent O(7)Mg4Fe square pyramids, corners with two equivalent O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(1)Mg3Fe3 octahedra, and  an edgeedge with one O(2)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. is represented by the CIF card [CIF]
data_MgFeO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.962
_cell_length_b   8.245
_cell_length_c   8.157
_cell_angle_alpha   87.241
_cell_angle_beta   79.432
_cell_angle_gamma   100.315
_symmetry_Int_Tables_number   1
_cell_volume   191.984
_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
  Mg  Mg0  1  0.381  0.051  0.312  1.0
  Mg  Mg1  1  0.616  0.929  0.716  1.0
  Mg  Mg2  1  0.322  0.759  0.127  1.0
  Mg  Mg3  1  0.676  0.221  0.901  1.0
  Fe  Fe4  1  0.342  0.263  0.591  1.0
  Fe  Fe5  1  0.087  0.388  0.219  1.0
  Fe  Fe6  1  0.907  0.591  0.810  1.0
  Fe  Fe7  1  0.651  0.717  0.438  1.0
  O  O8  1  0.127  0.817  0.574  1.0
  O  O9  1  0.341  0.413  0.779  1.0
  O  O10  1  0.653  0.567  0.249  1.0
  O  O11  1  0.871  0.163  0.454  1.0
  O  O12  1  0.157  0.085  0.800  1.0
  O  O13  1  0.563  0.246  0.138  1.0
  O  O14  1  0.841  0.894  0.228  1.0
  O  O15  1  0.432  0.734  0.890  1.0
[/CIF]
.
The material described by MgFeO2 crystallizes in the triclinic P1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(6), two equivalent O(4), and two equivalent O(7) atoms. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one O(4), one O(8), two equivalent O(1), and two equivalent O(5) atoms. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to one O(8), two equivalent O(3), and two equivalent O(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 5-coordinate geometry to one O(6), two equivalent O(2), and two equivalent O(5) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(5), and two equivalent O(4) atoms. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(3), and two equivalent O(6) atoms. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(8) atoms. In the fourth Fe site, Fe(4) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(7), and two equivalent O(1) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mg(2), one Fe(3), and two equivalent Fe(4) atoms to form distorted OMg3Fe3 octahedra that share corners with two equivalent O(5)Mg4Fe square pyramids,  a cornercorner with one O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(1)Mg3Fe3 octahedra, edges with two equivalent O(4)Mg3Fe3 octahedra,  an edgeedge with one O(5)Mg4Fe square pyramid, edges with two equivalent O(7)Mg4Fe square pyramids, and edges with two equivalent O(8)Mg2Fe2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Mg(4), one Fe(1), and two equivalent Fe(3) atoms to form distorted OMg2Fe3 trigonal bipyramids that share corners with two equivalent O(1)Mg3Fe3 octahedra, corners with two equivalent O(4)Mg3Fe3 octahedra, corners with two equivalent O(5)Mg4Fe square pyramids, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra,  an edgeedge with one O(8)Mg2Fe2 tetrahedra, edges with two equivalent O(2)Mg2Fe3 trigonal bipyramids, and  a faceface with one O(5)Mg4Fe square pyramid. The corner-sharing octahedral tilt angles range from 44-68°. In the third O site, O(3) is bonded to two equivalent Mg(3), one Fe(4), and two equivalent Fe(2) atoms to form distorted OMg2Fe3 trigonal bipyramids that share corners with two equivalent O(1)Mg3Fe3 octahedra, corners with two equivalent O(4)Mg3Fe3 octahedra, corners with two equivalent O(7)Mg4Fe square pyramids, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra,  an edgeedge with one O(6)Mg2Fe2 tetrahedra, edges with two equivalent O(3)Mg2Fe3 trigonal bipyramids, and  a faceface with one O(7)Mg4Fe square pyramid. The corner-sharing octahedral tilt angles range from 44-68°. In the fourth O site, O(4) is bonded to one Mg(2), two equivalent Mg(1), one Fe(2), and two equivalent Fe(1) atoms to form distorted OMg3Fe3 octahedra that share corners with two equivalent O(7)Mg4Fe square pyramids,  a cornercorner with one O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(1)Mg3Fe3 octahedra, edges with two equivalent O(4)Mg3Fe3 octahedra,  an edgeedge with one O(7)Mg4Fe square pyramid, edges with two equivalent O(5)Mg4Fe square pyramids, and edges with two equivalent O(6)Mg2Fe2 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Mg(2), two equivalent Mg(4), and one Fe(1) atom to form OMg4Fe square pyramids that share corners with two equivalent O(1)Mg3Fe3 octahedra, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids,  an edgeedge with one O(1)Mg3Fe3 octahedra, edges with two equivalent O(4)Mg3Fe3 octahedra, edges with two equivalent O(5)Mg4Fe square pyramids, and  a faceface with one O(2)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 15-16°. In the sixth O site, O(6) is bonded to one Mg(1), one Mg(4), and two equivalent Fe(2) atoms to form OMg2Fe2 tetrahedra that share  a cornercorner with one O(1)Mg3Fe3 octahedra, corners with two equivalent O(5)Mg4Fe square pyramids, corners with two equivalent O(7)Mg4Fe square pyramids, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(4)Mg3Fe3 octahedra, and  an edgeedge with one O(3)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. In the seventh O site, O(7) is bonded to two equivalent Mg(1), two equivalent Mg(3), and one Fe(4) atom to form OMg4Fe square pyramids that share corners with two equivalent O(4)Mg3Fe3 octahedra, corners with two equivalent O(6)Mg2Fe2 tetrahedra, corners with two equivalent O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids,  an edgeedge with one O(4)Mg3Fe3 octahedra, edges with two equivalent O(1)Mg3Fe3 octahedra, edges with two equivalent O(7)Mg4Fe square pyramids, and  a faceface with one O(3)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 15°. In the eighth O site, O(8) is bonded to one Mg(2), one Mg(3), and two equivalent Fe(3) atoms to form OMg2Fe2 tetrahedra that share  a cornercorner with one O(4)Mg3Fe3 octahedra, corners with two equivalent O(5)Mg4Fe square pyramids, corners with two equivalent O(7)Mg4Fe square pyramids, corners with two equivalent O(8)Mg2Fe2 tetrahedra, corners with two equivalent O(2)Mg2Fe3 trigonal bipyramids, corners with two equivalent O(3)Mg2Fe3 trigonal bipyramids, edges with two equivalent O(1)Mg3Fe3 octahedra, and  an edgeedge with one O(2)Mg2Fe3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. is represented by the CIF card [CIF]
data_MgFeO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.962
_cell_length_b   8.245
_cell_length_c   8.157
_cell_angle_alpha   87.241
_cell_angle_beta   79.432
_cell_angle_gamma   100.315
_symmetry_Int_Tables_number   1
_cell_volume   191.984
_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
  Mg  Mg0  1  0.381  0.051  0.312  1.0
  Mg  Mg1  1  0.616  0.929  0.716  1.0
  Mg  Mg2  1  0.322  0.759  0.127  1.0
  Mg  Mg3  1  0.676  0.221  0.901  1.0
  Fe  Fe4  1  0.342  0.263  0.591  1.0
  Fe  Fe5  1  0.087  0.388  0.219  1.0
  Fe  Fe6  1  0.907  0.591  0.810  1.0
  Fe  Fe7  1  0.651  0.717  0.438  1.0
  O  O8  1  0.127  0.817  0.574  1.0
  O  O9  1  0.341  0.413  0.779  1.0
  O  O10  1  0.653  0.567  0.249  1.0
  O  O11  1  0.871  0.163  0.454  1.0
  O  O12  1  0.157  0.085  0.800  1.0
  O  O13  1  0.563  0.246  0.138  1.0
  O  O14  1  0.841  0.894  0.228  1.0
  O  O15  1  0.432  0.734  0.890  1.0
[/CIF]
.