The compound 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), one O(6), and one O(8) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(6), one O(7), and one O(8) atom. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(6) atom. Mg(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form MgO4 tetrahedra that share corners with two equivalent Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. 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(6), one O(7), and one O(8) 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 two equivalent Mg(1)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(6), one Mg(1), and one Bi(1) atom. In the second O site, O(2) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(5), one Na(6), one Mg(1), and one Bi(1) atom. In the third O site, O(3) 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  a cornercorner with one O(7)Na3Bi2 trigonal bipyramid, edges with two equivalent O(6)Na4Bi2 octahedra, and  an edgeedge with one O(7)Na3Bi2 trigonal bipyramid. In the fourth O site, O(4) 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 fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(3), one Na(5), one Mg(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded to one Na(3), one Na(4), one Na(5), one Na(6), one Bi(1), and one Bi(2) atom to form ONa4Bi2 octahedra that share  a cornercorner with one O(7)Na3Bi2 trigonal bipyramid, edges with two equivalent O(3)Na5Bi octahedra, and  an edgeedge with one O(7)Na3Bi2 trigonal bipyramid. In the seventh O site, O(7) is bonded to one Na(1), one Na(2), one Na(4), one Bi(1), and one Bi(2) atom to form distorted ONa3Bi2 trigonal bipyramids that share  a cornercorner with one O(6)Na4Bi2 octahedra,  a cornercorner with one O(3)Na5Bi octahedra,  an edgeedge with one O(6)Na4Bi2 octahedra, and  an edgeedge with one O(3)Na5Bi octahedra. The corner-sharing octahedral tilt angles range from 62-74°. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Bi(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   6.183
_cell_length_b   6.233
_cell_length_c   6.718
_cell_angle_alpha   90.441
_cell_angle_beta   90.956
_cell_angle_gamma   113.520
_symmetry_Int_Tables_number   1
_cell_volume   237.308
_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  0.770  0.997  0.376  1.0
  Na  Na1  1  0.241  0.525  0.333  1.0
  Na  Na2  1  0.725  0.510  0.127  1.0
  Na  Na3  1  0.196  0.535  0.922  1.0
  Na  Na4  1  0.277  0.892  0.620  1.0
  Na  Na5  1  0.822  0.528  0.591  1.0
  Mg  Mg6  1  0.353  0.343  0.645  1.0
  Bi  Bi7  1  0.769  0.993  0.853  1.0
  Bi  Bi8  1  0.252  0.018  0.139  1.0
  O  O9  1  0.012  0.270  0.641  1.0
  O  O10  1  0.519  0.689  0.638  1.0
  O  O11  1  0.028  0.768  0.340  1.0
  O  O12  1  0.459  0.245  0.386  1.0
  O  O13  1  0.463  0.228  0.891  1.0
  O  O14  1  0.002  0.792  0.895  1.0
  O  O15  1  0.028  0.209  0.121  1.0
  O  O16  1  0.471  0.823  0.121  1.0
[/CIF]
.
The compound 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), one O(6), and one O(8) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(6), one O(7), and one O(8) atom. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(6) atom. Mg(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form MgO4 tetrahedra that share corners with two equivalent Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. 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(6), one O(7), and one O(8) 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 two equivalent Mg(1)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(6), one Mg(1), and one Bi(1) atom. In the second O site, O(2) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(5), one Na(6), one Mg(1), and one Bi(1) atom. In the third O site, O(3) 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  a cornercorner with one O(7)Na3Bi2 trigonal bipyramid, edges with two equivalent O(6)Na4Bi2 octahedra, and  an edgeedge with one O(7)Na3Bi2 trigonal bipyramid. In the fourth O site, O(4) 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 fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(3), one Na(5), one Mg(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded to one Na(3), one Na(4), one Na(5), one Na(6), one Bi(1), and one Bi(2) atom to form ONa4Bi2 octahedra that share  a cornercorner with one O(7)Na3Bi2 trigonal bipyramid, edges with two equivalent O(3)Na5Bi octahedra, and  an edgeedge with one O(7)Na3Bi2 trigonal bipyramid. In the seventh O site, O(7) is bonded to one Na(1), one Na(2), one Na(4), one Bi(1), and one Bi(2) atom to form distorted ONa3Bi2 trigonal bipyramids that share  a cornercorner with one O(6)Na4Bi2 octahedra,  a cornercorner with one O(3)Na5Bi octahedra,  an edgeedge with one O(6)Na4Bi2 octahedra, and  an edgeedge with one O(3)Na5Bi octahedra. The corner-sharing octahedral tilt angles range from 62-74°. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Bi(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   6.183
_cell_length_b   6.233
_cell_length_c   6.718
_cell_angle_alpha   90.441
_cell_angle_beta   90.956
_cell_angle_gamma   113.520
_symmetry_Int_Tables_number   1
_cell_volume   237.308
_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  0.770  0.997  0.376  1.0
  Na  Na1  1  0.241  0.525  0.333  1.0
  Na  Na2  1  0.725  0.510  0.127  1.0
  Na  Na3  1  0.196  0.535  0.922  1.0
  Na  Na4  1  0.277  0.892  0.620  1.0
  Na  Na5  1  0.822  0.528  0.591  1.0
  Mg  Mg6  1  0.353  0.343  0.645  1.0
  Bi  Bi7  1  0.769  0.993  0.853  1.0
  Bi  Bi8  1  0.252  0.018  0.139  1.0
  O  O9  1  0.012  0.270  0.641  1.0
  O  O10  1  0.519  0.689  0.638  1.0
  O  O11  1  0.028  0.768  0.340  1.0
  O  O12  1  0.459  0.245  0.386  1.0
  O  O13  1  0.463  0.228  0.891  1.0
  O  O14  1  0.002  0.792  0.895  1.0
  O  O15  1  0.028  0.209  0.121  1.0
  O  O16  1  0.471  0.823  0.121  1.0
[/CIF]
.