The material described by Mg3Cr6(FeO6)4 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, corners with two equivalent Cr(3)O4 tetrahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 57°. In the second Mg site, Mg(2) is bonded to one O(11), one O(2), one O(5), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Cr(2)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(3)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 60°. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(11), one O(3), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 24-62°. In the second Cr site, Cr(2) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(1)O6 octahedra, and  a cornercorner with one Mg(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-56°. In the third Cr site, Cr(3) is bonded to one O(12), one O(2), one O(5), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 24-65°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(6), one O(7), one O(9), and two equivalent O(4) atoms to form FeO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 57°. In the second Fe site, Fe(2) is bonded to one O(10), one O(11), one O(12), one O(5), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, corners with two equivalent Cr(3)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mg(1) and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one Cr(3) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Cr(1), and one Fe(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Fe(1) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(2), one Cr(3), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(2), one Cr(1), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mg(2), one Cr(2), and one Fe(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Fe(2) atoms. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Cr(3) and one Fe(1) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Mg(2), one Cr(1), and one Fe(2) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Cr(3) and one Fe(2) atom. is represented by the CIF card [CIF]
data_Mg3Cr6(FeO6)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.693
_cell_length_b   8.151
_cell_length_c   9.829
_cell_angle_alpha   104.807
_cell_angle_beta   105.896
_cell_angle_gamma   102.078
_symmetry_Int_Tables_number   1
_cell_volume   475.590
_cell_formula_units_Z   1
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  0.000  0.500  0.500  1.0
  Mg  Mg1  1  0.278  0.291  0.791  1.0
  Mg  Mg2  1  0.722  0.709  0.209  1.0
  Cr  Cr3  1  0.778  0.344  0.728  1.0
  Cr  Cr4  1  0.222  0.656  0.272  1.0
  Cr  Cr5  1  0.898  0.903  0.668  1.0
  Cr  Cr6  1  0.398  0.726  0.869  1.0
  Cr  Cr7  1  0.102  0.097  0.332  1.0
  Cr  Cr8  1  0.602  0.274  0.131  1.0
  Fe  Fe9  1  0.379  0.955  0.608  1.0
  Fe  Fe10  1  0.621  0.045  0.392  1.0
  Fe  Fe11  1  0.045  0.212  0.016  1.0
  Fe  Fe12  1  0.955  0.788  0.984  1.0
  O  O13  1  0.875  0.693  0.583  1.0
  O  O14  1  0.125  0.307  0.417  1.0
  O  O15  1  0.266  0.516  0.742  1.0
  O  O16  1  0.734  0.484  0.258  1.0
  O  O17  1  0.784  0.301  0.545  1.0
  O  O18  1  0.216  0.699  0.455  1.0
  O  O19  1  0.669  0.960  0.576  1.0
  O  O20  1  0.331  0.040  0.424  1.0
  O  O21  1  0.645  0.738  0.999  1.0
  O  O22  1  0.355  0.262  0.001  1.0
  O  O23  1  0.473  0.771  0.273  1.0
  O  O24  1  0.527  0.229  0.727  1.0
  O  O25  1  0.132  0.031  0.654  1.0
  O  O26  1  0.071  0.050  0.143  1.0
  O  O27  1  0.929  0.950  0.857  1.0
  O  O28  1  0.557  0.133  0.226  1.0
  O  O29  1  0.443  0.867  0.774  1.0
  O  O30  1  0.179  0.442  0.184  1.0
  O  O31  1  0.821  0.558  0.816  1.0
  O  O32  1  0.989  0.283  0.833  1.0
  O  O33  1  0.011  0.717  0.167  1.0
  O  O34  1  0.236  0.782  0.967  1.0
  O  O35  1  0.764  0.218  0.033  1.0
  O  O36  1  0.868  0.969  0.346  1.0
[/CIF]
.
The material described by Mg3Cr6(FeO6)4 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, corners with two equivalent Cr(3)O4 tetrahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 57°. In the second Mg site, Mg(2) is bonded to one O(11), one O(2), one O(5), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Cr(2)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(3)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 60°. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(11), one O(3), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 24-62°. In the second Cr site, Cr(2) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(1)O6 octahedra, and  a cornercorner with one Mg(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-56°. In the third Cr site, Cr(3) is bonded to one O(12), one O(2), one O(5), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 24-65°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(6), one O(7), one O(9), and two equivalent O(4) atoms to form FeO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 57°. In the second Fe site, Fe(2) is bonded to one O(10), one O(11), one O(12), one O(5), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, corners with two equivalent Cr(3)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mg(1) and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one Cr(3) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Cr(1), and one Fe(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Fe(1) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(2), one Cr(3), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(2), one Cr(1), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mg(2), one Cr(2), and one Fe(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Fe(2) atoms. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Cr(3) and one Fe(1) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Mg(2), one Cr(1), and one Fe(2) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Cr(3) and one Fe(2) atom. is represented by the CIF card [CIF]
data_Mg3Cr6(FeO6)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.693
_cell_length_b   8.151
_cell_length_c   9.829
_cell_angle_alpha   104.807
_cell_angle_beta   105.896
_cell_angle_gamma   102.078
_symmetry_Int_Tables_number   1
_cell_volume   475.590
_cell_formula_units_Z   1
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  0.000  0.500  0.500  1.0
  Mg  Mg1  1  0.278  0.291  0.791  1.0
  Mg  Mg2  1  0.722  0.709  0.209  1.0
  Cr  Cr3  1  0.778  0.344  0.728  1.0
  Cr  Cr4  1  0.222  0.656  0.272  1.0
  Cr  Cr5  1  0.898  0.903  0.668  1.0
  Cr  Cr6  1  0.398  0.726  0.869  1.0
  Cr  Cr7  1  0.102  0.097  0.332  1.0
  Cr  Cr8  1  0.602  0.274  0.131  1.0
  Fe  Fe9  1  0.379  0.955  0.608  1.0
  Fe  Fe10  1  0.621  0.045  0.392  1.0
  Fe  Fe11  1  0.045  0.212  0.016  1.0
  Fe  Fe12  1  0.955  0.788  0.984  1.0
  O  O13  1  0.875  0.693  0.583  1.0
  O  O14  1  0.125  0.307  0.417  1.0
  O  O15  1  0.266  0.516  0.742  1.0
  O  O16  1  0.734  0.484  0.258  1.0
  O  O17  1  0.784  0.301  0.545  1.0
  O  O18  1  0.216  0.699  0.455  1.0
  O  O19  1  0.669  0.960  0.576  1.0
  O  O20  1  0.331  0.040  0.424  1.0
  O  O21  1  0.645  0.738  0.999  1.0
  O  O22  1  0.355  0.262  0.001  1.0
  O  O23  1  0.473  0.771  0.273  1.0
  O  O24  1  0.527  0.229  0.727  1.0
  O  O25  1  0.132  0.031  0.654  1.0
  O  O26  1  0.071  0.050  0.143  1.0
  O  O27  1  0.929  0.950  0.857  1.0
  O  O28  1  0.557  0.133  0.226  1.0
  O  O29  1  0.443  0.867  0.774  1.0
  O  O30  1  0.179  0.442  0.184  1.0
  O  O31  1  0.821  0.558  0.816  1.0
  O  O32  1  0.989  0.283  0.833  1.0
  O  O33  1  0.011  0.717  0.167  1.0
  O  O34  1  0.236  0.782  0.967  1.0
  O  O35  1  0.764  0.218  0.033  1.0
  O  O36  1  0.868  0.969  0.346  1.0
[/CIF]
.