The crystal structure described by Na2MgNb2O6 crystallizes in the trigonal R-3 space group. Na(1) is bonded to six equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with nine equivalent Nb(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. Mg(1) is bonded to six equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with six equivalent Nb(1)O6 octahedra, and faces with two equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. Nb(1) is bonded to six equivalent O(1) atoms to form NbO6 octahedra that share corners with nine equivalent Na(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Nb(1)O6 octahedra, and  a faceface with one Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. O(1) is bonded to two equivalent Na(1), one Mg(1), and two equivalent Nb(1) atoms to form a mixture of distorted corner and edge-sharing ONa2MgNb2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2MgNb2O6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.335
_cell_length_b   5.335
_cell_length_c   6.496
_cell_angle_alpha   65.754
_cell_angle_beta   65.754
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   140.977
_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  0.333  0.333  1.000  1.0
  Na  Na1  1  0.667  0.667  0.000  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Nb  Nb3  1  0.154  0.154  0.537  1.0
  Nb  Nb4  1  0.846  0.846  0.463  1.0
  O  O5  1  0.902  0.240  0.304  1.0
  O  O6  1  0.240  0.553  0.304  1.0
  O  O7  1  0.553  0.902  0.304  1.0
  O  O8  1  0.098  0.760  0.696  1.0
  O  O9  1  0.760  0.447  0.696  1.0
  O  O10  1  0.447  0.098  0.696  1.0
[/CIF]
.
The crystal structure described by Na2MgNb2O6 crystallizes in the trigonal R-3 space group. Na(1) is bonded to six equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with nine equivalent Nb(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. Mg(1) is bonded to six equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with six equivalent Nb(1)O6 octahedra, and faces with two equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. Nb(1) is bonded to six equivalent O(1) atoms to form NbO6 octahedra that share corners with nine equivalent Na(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Nb(1)O6 octahedra, and  a faceface with one Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. O(1) is bonded to two equivalent Na(1), one Mg(1), and two equivalent Nb(1) atoms to form a mixture of distorted corner and edge-sharing ONa2MgNb2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2MgNb2O6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.335
_cell_length_b   5.335
_cell_length_c   6.496
_cell_angle_alpha   65.754
_cell_angle_beta   65.754
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   140.977
_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  0.333  0.333  1.000  1.0
  Na  Na1  1  0.667  0.667  0.000  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Nb  Nb3  1  0.154  0.154  0.537  1.0
  Nb  Nb4  1  0.846  0.846  0.463  1.0
  O  O5  1  0.902  0.240  0.304  1.0
  O  O6  1  0.240  0.553  0.304  1.0
  O  O7  1  0.553  0.902  0.304  1.0
  O  O8  1  0.098  0.760  0.696  1.0
  O  O9  1  0.760  0.447  0.696  1.0
  O  O10  1  0.447  0.098  0.696  1.0
[/CIF]
.