The material described by MgNd2Cr2O8 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 trigonal pyramids that share corners with two equivalent Cr(2)O4 tetrahedra and  an edgeedge with one Cr(1)O4 trigonal pyramid. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted CrO4 trigonal pyramids that share  an edgeedge with one Mg(1)O4 trigonal pyramid. In the second Cr site, Cr(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with two equivalent Mg(1)O4 trigonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(1), one Nd(2), and one Cr(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Nd(1), one Nd(2), and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Mg(1), one Nd(1), one Nd(2), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Nd(1), one Nd(2), and one Cr(2) atom. is represented by the CIF card [CIF]
data_Nd2MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.390
_cell_length_b   6.300
_cell_length_c   6.242
_cell_angle_alpha   105.279
_cell_angle_beta   105.910
_cell_angle_gamma   118.102
_symmetry_Int_Tables_number   1
_cell_volume   188.957
_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
  Nd  Nd0  1  0.128  0.878  0.256  1.0
  Nd  Nd1  1  0.902  0.152  0.803  1.0
  Mg  Mg2  1  0.612  0.862  0.223  1.0
  Cr  Cr3  1  0.355  0.605  0.709  1.0
  Cr  Cr4  1  0.625  0.375  0.250  1.0
  O  O5  1  0.784  0.738  0.422  1.0
  O  O6  1  0.385  0.798  0.545  1.0
  O  O7  1  0.715  0.810  0.949  1.0
  O  O8  1  0.807  0.387  0.077  1.0
  O  O9  1  0.638  0.184  0.422  1.0
  O  O10  1  0.160  0.247  0.545  1.0
  O  O11  1  0.235  0.640  0.949  1.0
  O  O12  1  0.270  0.190  0.077  1.0
[/CIF]
.
The material described by MgNd2Cr2O8 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 trigonal pyramids that share corners with two equivalent Cr(2)O4 tetrahedra and  an edgeedge with one Cr(1)O4 trigonal pyramid. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted CrO4 trigonal pyramids that share  an edgeedge with one Mg(1)O4 trigonal pyramid. In the second Cr site, Cr(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with two equivalent Mg(1)O4 trigonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(1), one Nd(2), and one Cr(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Nd(1), one Nd(2), and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Mg(1), one Nd(1), one Nd(2), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Nd(1), one Nd(2), and one Cr(2) atom. is represented by the CIF card [CIF]
data_Nd2MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.390
_cell_length_b   6.300
_cell_length_c   6.242
_cell_angle_alpha   105.279
_cell_angle_beta   105.910
_cell_angle_gamma   118.102
_symmetry_Int_Tables_number   1
_cell_volume   188.957
_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
  Nd  Nd0  1  0.128  0.878  0.256  1.0
  Nd  Nd1  1  0.902  0.152  0.803  1.0
  Mg  Mg2  1  0.612  0.862  0.223  1.0
  Cr  Cr3  1  0.355  0.605  0.709  1.0
  Cr  Cr4  1  0.625  0.375  0.250  1.0
  O  O5  1  0.784  0.738  0.422  1.0
  O  O6  1  0.385  0.798  0.545  1.0
  O  O7  1  0.715  0.810  0.949  1.0
  O  O8  1  0.807  0.387  0.077  1.0
  O  O9  1  0.638  0.184  0.422  1.0
  O  O10  1  0.160  0.247  0.545  1.0
  O  O11  1  0.235  0.640  0.949  1.0
  O  O12  1  0.270  0.190  0.077  1.0
[/CIF]
.