The material described by Na2MgMn2O8 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with six equivalent Mn(1)O4 tetrahedra and edges with two equivalent Na(2)O6 octahedra. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with six equivalent Mn(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Mn(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted MnO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and corners with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Mg(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one Mg(1), and one Mn(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Na(1) and one Mn(1) atom. is represented by the CIF file [CIF]
data_Na2MgMn2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.485
_cell_length_b   5.485
_cell_length_c   7.197
_cell_angle_alpha   87.087
_cell_angle_beta   87.087
_cell_angle_gamma   68.890
_symmetry_Int_Tables_number   1
_cell_volume   201.589
_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  0.000  0.000  0.000  1.0
  Na  Na1  1  0.000  0.000  0.500  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mn  Mn3  1  0.645  0.645  0.772  1.0
  Mn  Mn4  1  0.355  0.355  0.228  1.0
  O  O5  1  0.257  0.681  0.261  1.0
  O  O6  1  0.319  0.743  0.739  1.0
  O  O7  1  0.740  0.740  0.564  1.0
  O  O8  1  0.250  0.250  0.055  1.0
  O  O9  1  0.260  0.260  0.436  1.0
  O  O10  1  0.750  0.750  0.945  1.0
  O  O11  1  0.681  0.257  0.261  1.0
  O  O12  1  0.743  0.319  0.739  1.0
[/CIF]
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The material described by Na2MgMn2O8 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with six equivalent Mn(1)O4 tetrahedra and edges with two equivalent Na(2)O6 octahedra. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with six equivalent Mn(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Mn(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted MnO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and corners with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Mg(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one Mg(1), and one Mn(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Na(1) and one Mn(1) atom. is represented by the CIF file [CIF]
data_Na2MgMn2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.485
_cell_length_b   5.485
_cell_length_c   7.197
_cell_angle_alpha   87.087
_cell_angle_beta   87.087
_cell_angle_gamma   68.890
_symmetry_Int_Tables_number   1
_cell_volume   201.589
_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  0.000  0.000  0.000  1.0
  Na  Na1  1  0.000  0.000  0.500  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mn  Mn3  1  0.645  0.645  0.772  1.0
  Mn  Mn4  1  0.355  0.355  0.228  1.0
  O  O5  1  0.257  0.681  0.261  1.0
  O  O6  1  0.319  0.743  0.739  1.0
  O  O7  1  0.740  0.740  0.564  1.0
  O  O8  1  0.250  0.250  0.055  1.0
  O  O9  1  0.260  0.260  0.436  1.0
  O  O10  1  0.750  0.750  0.945  1.0
  O  O11  1  0.681  0.257  0.261  1.0
  O  O12  1  0.743  0.319  0.739  1.0
[/CIF]
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