The crystal structure described by Na4MgCr2O8 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(2) and two equivalent O(4) atoms. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(3), and two equivalent O(4) atoms. Mg(1) is bonded in a 4-coordinate geometry to two equivalent O(2) and two equivalent O(3) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a tetrahedral geometry to two equivalent O(2) and two equivalent O(3) atoms. In the second Cr site, Cr(2) is bonded in a tetrahedral geometry to two equivalent O(1) and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(3), and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(2), one Mg(1), and one Cr(1) atom. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(3), one Mg(1), and one Cr(1) atom to form a mixture of distorted edge and face-sharing ONa3MgCr trigonal bipyramids. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(3), and one Cr(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.823
_cell_length_b   5.823
_cell_length_c   7.306
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   119.262
_symmetry_Int_Tables_number   1
_cell_volume   216.075
_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
  Na  Na0  1  0.198  0.802  0.750  1.0
  Na  Na1  1  0.801  0.199  0.250  1.0
  Na  Na2  1  0.441  0.559  0.471  1.0
  Na  Na3  1  0.441  0.559  0.029  1.0
  Mg  Mg4  1  0.639  0.361  0.750  1.0
  Cr  Cr5  1  0.908  0.092  0.750  1.0
  Cr  Cr6  1  0.114  0.886  0.250  1.0
  O  O7  1  0.212  0.788  0.067  1.0
  O  O8  1  0.785  0.215  0.568  1.0
  O  O9  1  0.785  0.215  0.932  1.0
  O  O10  1  0.212  0.788  0.433  1.0
  O  O11  1  0.264  0.249  0.750  1.0
  O  O12  1  0.785  0.752  0.250  1.0
  O  O13  1  0.751  0.736  0.750  1.0
  O  O14  1  0.248  0.215  0.250  1.0
[/CIF]
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The crystal structure described by Na4MgCr2O8 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(2) and two equivalent O(4) atoms. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(3), and two equivalent O(4) atoms. Mg(1) is bonded in a 4-coordinate geometry to two equivalent O(2) and two equivalent O(3) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a tetrahedral geometry to two equivalent O(2) and two equivalent O(3) atoms. In the second Cr site, Cr(2) is bonded in a tetrahedral geometry to two equivalent O(1) and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(3), and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(2), one Mg(1), and one Cr(1) atom. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(3), one Mg(1), and one Cr(1) atom to form a mixture of distorted edge and face-sharing ONa3MgCr trigonal bipyramids. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(3), and one Cr(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4MgCr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.823
_cell_length_b   5.823
_cell_length_c   7.306
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   119.262
_symmetry_Int_Tables_number   1
_cell_volume   216.075
_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
  Na  Na0  1  0.198  0.802  0.750  1.0
  Na  Na1  1  0.801  0.199  0.250  1.0
  Na  Na2  1  0.441  0.559  0.471  1.0
  Na  Na3  1  0.441  0.559  0.029  1.0
  Mg  Mg4  1  0.639  0.361  0.750  1.0
  Cr  Cr5  1  0.908  0.092  0.750  1.0
  Cr  Cr6  1  0.114  0.886  0.250  1.0
  O  O7  1  0.212  0.788  0.067  1.0
  O  O8  1  0.785  0.215  0.568  1.0
  O  O9  1  0.785  0.215  0.932  1.0
  O  O10  1  0.212  0.788  0.433  1.0
  O  O11  1  0.264  0.249  0.750  1.0
  O  O12  1  0.785  0.752  0.250  1.0
  O  O13  1  0.751  0.736  0.750  1.0
  O  O14  1  0.248  0.215  0.250  1.0
[/CIF]
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