The material described by MgNbCrO4 crystallizes in the orthorhombic Imm2 space group. Mg(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, corners with four equivalent Mg(1)O5 trigonal bipyramids, edges with two equivalent Cr(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-72°. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, edges with four equivalent Cr(1)O6 octahedra, and edges with four equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 3-7°. Cr(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, edges with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-36°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), two equivalent Nb(1), and one Cr(1) atom to form a mixture of edge and corner-sharing OMg2Nb2Cr trigonal bipyramids. In the second O site, O(2) is bonded in a square co-planar geometry to one Mg(1), one Nb(1), and two equivalent Cr(1) atoms. In the third O site, O(3) is bonded to two equivalent Mg(1), two equivalent Nb(1), and one Cr(1) atom to form a mixture of distorted edge and corner-sharing OMg2Nb2Cr square pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Nb(1) and two equivalent Cr(1) atoms. is represented by the CIF file [CIF]
data_MgNbCrO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.687
_cell_length_b   5.687
_cell_length_c   5.687
_cell_angle_alpha   137.895
_cell_angle_beta   136.088
_cell_angle_gamma   62.463
_symmetry_Int_Tables_number   1
_cell_volume   84.516
_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  0.430  0.430  0.000  1.0
  Nb  Nb1  1  0.004  0.004  0.000  1.0
  Cr  Cr2  1  0.732  0.232  0.500  1.0
  O  O3  1  0.499  0.999  0.500  1.0
  O  O4  1  0.222  0.222  0.000  1.0
  O  O5  1  0.991  0.491  0.500  1.0
  O  O6  1  0.799  0.799  0.000  1.0
[/CIF]
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The material described by MgNbCrO4 crystallizes in the orthorhombic Imm2 space group. Mg(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, corners with four equivalent Mg(1)O5 trigonal bipyramids, edges with two equivalent Cr(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-72°. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, edges with four equivalent Cr(1)O6 octahedra, and edges with four equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 3-7°. Cr(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, edges with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-36°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), two equivalent Nb(1), and one Cr(1) atom to form a mixture of edge and corner-sharing OMg2Nb2Cr trigonal bipyramids. In the second O site, O(2) is bonded in a square co-planar geometry to one Mg(1), one Nb(1), and two equivalent Cr(1) atoms. In the third O site, O(3) is bonded to two equivalent Mg(1), two equivalent Nb(1), and one Cr(1) atom to form a mixture of distorted edge and corner-sharing OMg2Nb2Cr square pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Nb(1) and two equivalent Cr(1) atoms. is represented by the CIF file [CIF]
data_MgNbCrO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.687
_cell_length_b   5.687
_cell_length_c   5.687
_cell_angle_alpha   137.895
_cell_angle_beta   136.088
_cell_angle_gamma   62.463
_symmetry_Int_Tables_number   1
_cell_volume   84.516
_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  0.430  0.430  0.000  1.0
  Nb  Nb1  1  0.004  0.004  0.000  1.0
  Cr  Cr2  1  0.732  0.232  0.500  1.0
  O  O3  1  0.499  0.999  0.500  1.0
  O  O4  1  0.222  0.222  0.000  1.0
  O  O5  1  0.991  0.491  0.500  1.0
  O  O6  1  0.799  0.799  0.000  1.0
[/CIF]
.