The crystal structure described by Na2MgMn2O8 crystallizes in the orthorhombic Amm2 space group. Na(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NaO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra, corners with three equivalent Mn(2)O4 tetrahedra, and edges with two equivalent Na(1)O6 octahedra. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra, corners with two equivalent Mn(1)O4 tetrahedra, and  an edgeedge with one Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-69°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form MnO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-52°. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form MnO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-54°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), one Mg(1), and one Mn(2) atom to form distorted edge-sharing ONa2MgMn tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one Mn(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Na(1), one Mg(1), and one Mn(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Na(1) and one Mn(2) atom. is represented by the CIF file [CIF]
data_Na2MgMn2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.585
_cell_length_b   5.581
_cell_length_c   6.454
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   66.750
_symmetry_Int_Tables_number   1
_cell_volume   184.834
_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  0.999  1.000  0.995  1.0
  Na  Na1  1  0.999  1.000  0.505  1.0
  Mg  Mg2  1  0.649  0.651  0.250  1.0
  Mn  Mn3  1  0.640  0.640  0.750  1.0
  Mn  Mn4  1  0.357  0.358  0.250  1.0
  O  O5  1  0.270  0.693  0.250  1.0
  O  O6  1  0.322  0.763  0.750  1.0
  O  O7  1  0.742  0.743  0.530  1.0
  O  O8  1  0.263  0.263  0.041  1.0
  O  O9  1  0.263  0.263  0.459  1.0
  O  O10  1  0.742  0.743  0.970  1.0
  O  O11  1  0.692  0.271  0.250  1.0
  O  O12  1  0.763  0.322  0.750  1.0
[/CIF]
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The crystal structure described by Na2MgMn2O8 crystallizes in the orthorhombic Amm2 space group. Na(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NaO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra, corners with three equivalent Mn(2)O4 tetrahedra, and edges with two equivalent Na(1)O6 octahedra. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra, corners with two equivalent Mn(1)O4 tetrahedra, and  an edgeedge with one Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-69°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form MnO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-52°. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form MnO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-54°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), one Mg(1), and one Mn(2) atom to form distorted edge-sharing ONa2MgMn tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one Mn(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Na(1), one Mg(1), and one Mn(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Na(1) and one Mn(2) atom. is represented by the CIF file [CIF]
data_Na2MgMn2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.585
_cell_length_b   5.581
_cell_length_c   6.454
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   66.750
_symmetry_Int_Tables_number   1
_cell_volume   184.834
_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  0.999  1.000  0.995  1.0
  Na  Na1  1  0.999  1.000  0.505  1.0
  Mg  Mg2  1  0.649  0.651  0.250  1.0
  Mn  Mn3  1  0.640  0.640  0.750  1.0
  Mn  Mn4  1  0.357  0.358  0.250  1.0
  O  O5  1  0.270  0.693  0.250  1.0
  O  O6  1  0.322  0.763  0.750  1.0
  O  O7  1  0.742  0.743  0.530  1.0
  O  O8  1  0.263  0.263  0.041  1.0
  O  O9  1  0.263  0.263  0.459  1.0
  O  O10  1  0.742  0.743  0.970  1.0
  O  O11  1  0.692  0.271  0.250  1.0
  O  O12  1  0.763  0.322  0.750  1.0
[/CIF]
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