The structure described by Na6Mg(BiO4)2 crystallizes in the triclinic P1 space group. There are six inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(8) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(5), and one O(8) atom to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(5)O6 octahedra, corners with two equivalent Bi(2)O6 octahedra, corners with two equivalent Na(6)O5 square pyramids, and  an edgeedge with one Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-89°. In the fifth Na site, Na(5) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share corners with three equivalent Na(6)O5 square pyramids,  a cornercorner with one Na(4)O4 tetrahedra, edges with two equivalent Bi(2)O6 octahedra,  an edgeedge with one Na(6)O5 square pyramid, and  an edgeedge with one Na(4)O4 tetrahedra. In the sixth Na site, Na(6) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted NaO5 square pyramids that share corners with three equivalent Na(5)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra, corners with two equivalent Na(4)O4 tetrahedra, and  an edgeedge with one Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-83°. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(3), one O(6), one O(7), and one O(8) atom. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(5), one O(6), and one O(7) atom. In the second Bi site, Bi(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Na(6)O5 square pyramids, corners with two equivalent Na(4)O4 tetrahedra, and edges with two equivalent Na(5)O6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Na(6), and one Bi(1) atom to form distorted ONa5Bi octahedra that share corners with two equivalent O(2)Na5Bi octahedra,  a cornercorner with one O(6)Na2MgBi2 trigonal bipyramid, edges with two equivalent O(2)Na5Bi octahedra, edges with two equivalent O(4)Na5Bi octahedra, and  an edgeedge with one O(6)Na2MgBi2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 8-14°. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Na(6), and one Bi(1) atom to form ONa5Bi octahedra that share corners with two equivalent O(1)Na5Bi octahedra,  a cornercorner with one O(6)Na2MgBi2 trigonal bipyramid, edges with two equivalent O(1)Na5Bi octahedra, edges with two equivalent O(4)Na5Bi octahedra, and  an edgeedge with one O(6)Na2MgBi2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 8-14°. In the third O site, O(3) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(5), one Na(6), one Mg(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(5), one Na(6), and one Bi(2) atom to form ONa5Bi octahedra that share corners with three equivalent O(6)Na2MgBi2 trigonal bipyramids, edges with two equivalent O(1)Na5Bi octahedra, and edges with two equivalent O(2)Na5Bi octahedra. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(5), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded to one Na(5), one Na(6), one Mg(1), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing ONa2MgBi2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-92°. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one Bi(2) atom. is represented by the CIF file [CIF]
data_Na6Mg(BiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.248
_cell_length_b   6.061
_cell_length_c   6.948
_cell_angle_alpha   91.764
_cell_angle_beta   91.886
_cell_angle_gamma   112.204
_symmetry_Int_Tables_number   1
_cell_volume   243.228
_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  0.757  0.034  0.378  1.0
  Na  Na1  1  0.246  0.486  0.424  1.0
  Na  Na2  1  0.632  0.554  0.190  1.0
  Na  Na3  1  0.350  0.476  0.808  1.0
  Na  Na4  1  0.260  0.976  0.621  1.0
  Na  Na5  1  0.791  0.518  0.597  1.0
  Mg  Mg6  1  0.053  0.537  0.065  1.0
  Bi  Bi7  1  0.761  0.997  0.844  1.0
  Bi  Bi8  1  0.265  0.022  0.138  1.0
  O  O9  1  0.987  0.262  0.665  1.0
  O  O10  1  0.562  0.757  0.607  1.0
  O  O11  1  0.017  0.733  0.303  1.0
  O  O12  1  0.467  0.223  0.377  1.0
  O  O13  1  0.507  0.232  0.937  1.0
  O  O14  1  0.017  0.788  0.891  1.0
  O  O15  1  0.043  0.226  0.143  1.0
  O  O16  1  0.399  0.741  0.097  1.0
[/CIF]
.
The structure described by Na6Mg(BiO4)2 crystallizes in the triclinic P1 space group. There are six inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(8) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(5), and one O(8) atom to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(5)O6 octahedra, corners with two equivalent Bi(2)O6 octahedra, corners with two equivalent Na(6)O5 square pyramids, and  an edgeedge with one Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-89°. In the fifth Na site, Na(5) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share corners with three equivalent Na(6)O5 square pyramids,  a cornercorner with one Na(4)O4 tetrahedra, edges with two equivalent Bi(2)O6 octahedra,  an edgeedge with one Na(6)O5 square pyramid, and  an edgeedge with one Na(4)O4 tetrahedra. In the sixth Na site, Na(6) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted NaO5 square pyramids that share corners with three equivalent Na(5)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra, corners with two equivalent Na(4)O4 tetrahedra, and  an edgeedge with one Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-83°. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(3), one O(6), one O(7), and one O(8) atom. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(5), one O(6), and one O(7) atom. In the second Bi site, Bi(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Na(6)O5 square pyramids, corners with two equivalent Na(4)O4 tetrahedra, and edges with two equivalent Na(5)O6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Na(6), and one Bi(1) atom to form distorted ONa5Bi octahedra that share corners with two equivalent O(2)Na5Bi octahedra,  a cornercorner with one O(6)Na2MgBi2 trigonal bipyramid, edges with two equivalent O(2)Na5Bi octahedra, edges with two equivalent O(4)Na5Bi octahedra, and  an edgeedge with one O(6)Na2MgBi2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 8-14°. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Na(6), and one Bi(1) atom to form ONa5Bi octahedra that share corners with two equivalent O(1)Na5Bi octahedra,  a cornercorner with one O(6)Na2MgBi2 trigonal bipyramid, edges with two equivalent O(1)Na5Bi octahedra, edges with two equivalent O(4)Na5Bi octahedra, and  an edgeedge with one O(6)Na2MgBi2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 8-14°. In the third O site, O(3) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(5), one Na(6), one Mg(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(5), one Na(6), and one Bi(2) atom to form ONa5Bi octahedra that share corners with three equivalent O(6)Na2MgBi2 trigonal bipyramids, edges with two equivalent O(1)Na5Bi octahedra, and edges with two equivalent O(2)Na5Bi octahedra. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(5), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded to one Na(5), one Na(6), one Mg(1), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing ONa2MgBi2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-92°. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one Bi(2) atom. is represented by the CIF file [CIF]
data_Na6Mg(BiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.248
_cell_length_b   6.061
_cell_length_c   6.948
_cell_angle_alpha   91.764
_cell_angle_beta   91.886
_cell_angle_gamma   112.204
_symmetry_Int_Tables_number   1
_cell_volume   243.228
_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  0.757  0.034  0.378  1.0
  Na  Na1  1  0.246  0.486  0.424  1.0
  Na  Na2  1  0.632  0.554  0.190  1.0
  Na  Na3  1  0.350  0.476  0.808  1.0
  Na  Na4  1  0.260  0.976  0.621  1.0
  Na  Na5  1  0.791  0.518  0.597  1.0
  Mg  Mg6  1  0.053  0.537  0.065  1.0
  Bi  Bi7  1  0.761  0.997  0.844  1.0
  Bi  Bi8  1  0.265  0.022  0.138  1.0
  O  O9  1  0.987  0.262  0.665  1.0
  O  O10  1  0.562  0.757  0.607  1.0
  O  O11  1  0.017  0.733  0.303  1.0
  O  O12  1  0.467  0.223  0.377  1.0
  O  O13  1  0.507  0.232  0.937  1.0
  O  O14  1  0.017  0.788  0.891  1.0
  O  O15  1  0.043  0.226  0.143  1.0
  O  O16  1  0.399  0.741  0.097  1.0
[/CIF]
.