The crystal structure described by Na2MgNb(PO4)3 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(12), one O(2), one O(4), one O(5), one O(7), and one O(9) atom. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to one O(10), one O(11), one O(12), one O(7), one O(8), and one O(9) atom. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(3)O4 tetrahedra. Nb(1) is bonded to one O(10), one O(11), one O(12), one O(4), one O(5), and one O(6) atom to form NbO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(3)O4 tetrahedra. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), one O(5), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-37°. In the second P site, P(2) is bonded to one O(11), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-34°. In the third P site, P(3) is bonded to one O(12), one O(3), one O(6), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-36°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Mg(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Mg(1), and one P(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Nb(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Nb(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(3) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Mg(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Mg(1), and one P(1) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Mg(1), and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Nb(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one P(2) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(2), one Nb(1), and one P(3) atom. is represented by the CIF card [CIF]
data_Na2MgNb(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.802
_cell_length_b   8.864
_cell_length_c   9.064
_cell_angle_alpha   119.157
_cell_angle_beta   90.000
_cell_angle_gamma   119.769
_symmetry_Int_Tables_number   1
_cell_volume   508.064
_cell_formula_units_Z   2
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
  Mg  Mg0  1  0.358  0.710  0.057  1.0
  Mg  Mg1  1  0.852  0.710  0.557  1.0
  Na  Na2  1  0.890  0.505  0.744  1.0
  Na  Na3  1  0.116  0.505  0.244  1.0
  Na  Na4  1  0.496  0.989  0.481  1.0
  Na  Na5  1  0.993  0.989  0.981  1.0
  Nb  Nb6  1  0.639  0.288  0.940  1.0
  Nb  Nb7  1  0.149  0.288  0.440  1.0
  O  O8  1  0.122  0.408  0.926  1.0
  O  O9  1  0.273  0.781  0.911  1.0
  O  O10  1  0.510  0.636  0.918  1.0
  O  O11  1  0.786  0.408  0.426  1.0
  O  O12  1  0.626  0.636  0.418  1.0
  O  O13  1  0.008  0.781  0.411  1.0
  O  O14  1  0.867  0.591  0.079  1.0
  O  O15  1  0.727  0.226  0.092  1.0
  O  O16  1  0.495  0.363  0.086  1.0
  O  O17  1  0.224  0.591  0.579  1.0
  O  O18  1  0.369  0.363  0.586  1.0
  O  O19  1  0.999  0.226  0.592  1.0
  O  O20  1  0.213  0.795  0.226  1.0
  O  O21  1  0.585  0.013  0.230  1.0
  O  O22  1  0.419  0.640  0.230  1.0
  O  O23  1  0.082  0.795  0.726  1.0
  O  O24  1  0.721  0.640  0.730  1.0
  O  O25  1  0.928  0.013  0.730  1.0
  O  O26  1  0.784  0.213  0.769  1.0
  O  O27  1  0.425  0.986  0.771  1.0
  O  O28  1  0.564  0.344  0.769  1.0
  O  O29  1  0.929  0.213  0.269  1.0
  O  O30  1  0.280  0.344  0.269  1.0
  O  O31  1  0.061  0.986  0.271  1.0
  P  P32  1  0.965  0.211  0.760  1.0
  P  P33  1  0.249  0.790  0.753  1.0
  P  P34  1  0.546  0.510  0.758  1.0
  P  P35  1  0.746  0.211  0.260  1.0
  P  P36  1  0.464  0.510  0.258  1.0
  P  P37  1  0.041  0.790  0.253  1.0
[/CIF]
.
The crystal structure described by Na2MgNb(PO4)3 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(12), one O(2), one O(4), one O(5), one O(7), and one O(9) atom. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to one O(10), one O(11), one O(12), one O(7), one O(8), and one O(9) atom. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(3)O4 tetrahedra. Nb(1) is bonded to one O(10), one O(11), one O(12), one O(4), one O(5), and one O(6) atom to form NbO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(3)O4 tetrahedra. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), one O(5), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-37°. In the second P site, P(2) is bonded to one O(11), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-34°. In the third P site, P(3) is bonded to one O(12), one O(3), one O(6), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-36°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Mg(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Mg(1), and one P(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Nb(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Nb(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(3) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Mg(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Mg(1), and one P(1) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Mg(1), and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Nb(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one P(2) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(2), one Nb(1), and one P(3) atom. is represented by the CIF card [CIF]
data_Na2MgNb(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.802
_cell_length_b   8.864
_cell_length_c   9.064
_cell_angle_alpha   119.157
_cell_angle_beta   90.000
_cell_angle_gamma   119.769
_symmetry_Int_Tables_number   1
_cell_volume   508.064
_cell_formula_units_Z   2
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
  Mg  Mg0  1  0.358  0.710  0.057  1.0
  Mg  Mg1  1  0.852  0.710  0.557  1.0
  Na  Na2  1  0.890  0.505  0.744  1.0
  Na  Na3  1  0.116  0.505  0.244  1.0
  Na  Na4  1  0.496  0.989  0.481  1.0
  Na  Na5  1  0.993  0.989  0.981  1.0
  Nb  Nb6  1  0.639  0.288  0.940  1.0
  Nb  Nb7  1  0.149  0.288  0.440  1.0
  O  O8  1  0.122  0.408  0.926  1.0
  O  O9  1  0.273  0.781  0.911  1.0
  O  O10  1  0.510  0.636  0.918  1.0
  O  O11  1  0.786  0.408  0.426  1.0
  O  O12  1  0.626  0.636  0.418  1.0
  O  O13  1  0.008  0.781  0.411  1.0
  O  O14  1  0.867  0.591  0.079  1.0
  O  O15  1  0.727  0.226  0.092  1.0
  O  O16  1  0.495  0.363  0.086  1.0
  O  O17  1  0.224  0.591  0.579  1.0
  O  O18  1  0.369  0.363  0.586  1.0
  O  O19  1  0.999  0.226  0.592  1.0
  O  O20  1  0.213  0.795  0.226  1.0
  O  O21  1  0.585  0.013  0.230  1.0
  O  O22  1  0.419  0.640  0.230  1.0
  O  O23  1  0.082  0.795  0.726  1.0
  O  O24  1  0.721  0.640  0.730  1.0
  O  O25  1  0.928  0.013  0.730  1.0
  O  O26  1  0.784  0.213  0.769  1.0
  O  O27  1  0.425  0.986  0.771  1.0
  O  O28  1  0.564  0.344  0.769  1.0
  O  O29  1  0.929  0.213  0.269  1.0
  O  O30  1  0.280  0.344  0.269  1.0
  O  O31  1  0.061  0.986  0.271  1.0
  P  P32  1  0.965  0.211  0.760  1.0
  P  P33  1  0.249  0.790  0.753  1.0
  P  P34  1  0.546  0.510  0.758  1.0
  P  P35  1  0.746  0.211  0.260  1.0
  P  P36  1  0.464  0.510  0.258  1.0
  P  P37  1  0.041  0.790  0.253  1.0
[/CIF]
.