The structure described by Na8MgV2O8 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one V(2)O4 tetrahedra, corners with two equivalent V(1)O4 tetrahedra,  an edgeedge with one V(2)O4 tetrahedra, edges with two equivalent Na(4)O5 trigonal bipyramids, and  an edgeedge with one Na(5)O4 trigonal pyramid. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one V(1)O4 tetrahedra,  a cornercorner with one Na(5)O4 trigonal pyramid, edges with two equivalent Na(1)O5 square pyramids,  an edgeedge with one V(1)O4 tetrahedra,  an edgeedge with one V(2)O4 tetrahedra, and  an edgeedge with one Na(5)O4 trigonal pyramid. In the fifth Na site, Na(5) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one V(2)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid,  an edgeedge with one Na(1)O5 square pyramid,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Na(4)O5 trigonal bipyramid. In the sixth Na site, Na(6) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(7), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 4-coordinate geometry to one O(2), one O(6), one O(7), and one O(8) atom. In the eighth Na site, Na(8) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(6), and one O(7) atom. Mg(1) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid, corners with two equivalent V(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid,  an edgeedge with one V(2)O4 tetrahedra, and  an edgeedge with one Na(5)O4 trigonal pyramid. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share corners with two equivalent Na(1)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid, corners with three equivalent Na(5)O4 trigonal pyramids, and  an edgeedge with one Na(4)O5 trigonal bipyramid. In the second V site, V(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form VO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid,  a cornercorner with one Na(5)O4 trigonal pyramid,  an edgeedge with one Na(1)O5 square pyramid,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Na(4)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one V(2) atom to form edge-sharing ONa5V octahedra. In the second O site, O(2) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(7), one Na(8), and one V(2) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom to form a mixture of distorted corner and edge-sharing ONa5V octahedra. The corner-sharing octahedral tilt angles range from 13-23°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom to form a mixture of distorted corner and edge-sharing ONa5V octahedra. The corner-sharing octahedral tilt angles range from 13-23°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Mg(1), and one V(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(6), one Na(7), one Na(8), one Mg(1), and one V(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(6), one Na(7), one Na(8), one Mg(1), and one V(2) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(5), one Na(6), one Na(7), one Mg(1), and one V(2) atom. is represented by the CIF file [CIF]
data_Na8MgV2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.269
_cell_length_b   5.637
_cell_length_c   5.992
_cell_angle_alpha   70.874
_cell_angle_beta   110.499
_cell_angle_gamma   98.642
_symmetry_Int_Tables_number   1
_cell_volume   276.807
_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  0.172  0.022  0.641  1.0
  Na  Na1  1  0.168  0.517  0.152  1.0
  Na  Na2  1  0.321  0.535  0.725  1.0
  Na  Na3  1  0.341  0.034  0.247  1.0
  Na  Na4  1  0.518  0.015  0.821  1.0
  Na  Na5  1  0.731  0.517  0.923  1.0
  Na  Na6  1  0.806  0.861  0.287  1.0
  Na  Na7  1  0.964  0.520  0.604  1.0
  Mg  Mg8  1  0.721  0.086  0.571  1.0
  V  V9  1  0.505  0.566  0.346  1.0
  V  V10  1  0.998  0.009  0.980  1.0
  O  O11  1  0.145  0.261  0.902  1.0
  O  O12  1  0.079  0.788  0.309  1.0
  O  O13  1  0.374  0.751  0.026  1.0
  O  O14  1  0.375  0.312  0.497  1.0
  O  O15  1  0.562  0.808  0.542  1.0
  O  O16  1  0.689  0.436  0.329  1.0
  O  O17  1  0.914  0.888  0.684  1.0
  O  O18  1  0.787  0.132  0.910  1.0
[/CIF]
.
The structure described by Na8MgV2O8 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one V(2)O4 tetrahedra, corners with two equivalent V(1)O4 tetrahedra,  an edgeedge with one V(2)O4 tetrahedra, edges with two equivalent Na(4)O5 trigonal bipyramids, and  an edgeedge with one Na(5)O4 trigonal pyramid. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one V(1)O4 tetrahedra,  a cornercorner with one Na(5)O4 trigonal pyramid, edges with two equivalent Na(1)O5 square pyramids,  an edgeedge with one V(1)O4 tetrahedra,  an edgeedge with one V(2)O4 tetrahedra, and  an edgeedge with one Na(5)O4 trigonal pyramid. In the fifth Na site, Na(5) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one V(2)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid,  an edgeedge with one Na(1)O5 square pyramid,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Na(4)O5 trigonal bipyramid. In the sixth Na site, Na(6) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(7), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 4-coordinate geometry to one O(2), one O(6), one O(7), and one O(8) atom. In the eighth Na site, Na(8) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(6), and one O(7) atom. Mg(1) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid, corners with two equivalent V(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid,  an edgeedge with one V(2)O4 tetrahedra, and  an edgeedge with one Na(5)O4 trigonal pyramid. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share corners with two equivalent Na(1)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid, corners with three equivalent Na(5)O4 trigonal pyramids, and  an edgeedge with one Na(4)O5 trigonal bipyramid. In the second V site, V(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form VO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid,  a cornercorner with one Na(5)O4 trigonal pyramid,  an edgeedge with one Na(1)O5 square pyramid,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Na(4)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one V(2) atom to form edge-sharing ONa5V octahedra. In the second O site, O(2) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(7), one Na(8), and one V(2) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom to form a mixture of distorted corner and edge-sharing ONa5V octahedra. The corner-sharing octahedral tilt angles range from 13-23°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom to form a mixture of distorted corner and edge-sharing ONa5V octahedra. The corner-sharing octahedral tilt angles range from 13-23°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Mg(1), and one V(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(6), one Na(7), one Na(8), one Mg(1), and one V(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(6), one Na(7), one Na(8), one Mg(1), and one V(2) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(5), one Na(6), one Na(7), one Mg(1), and one V(2) atom. is represented by the CIF file [CIF]
data_Na8MgV2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.269
_cell_length_b   5.637
_cell_length_c   5.992
_cell_angle_alpha   70.874
_cell_angle_beta   110.499
_cell_angle_gamma   98.642
_symmetry_Int_Tables_number   1
_cell_volume   276.807
_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  0.172  0.022  0.641  1.0
  Na  Na1  1  0.168  0.517  0.152  1.0
  Na  Na2  1  0.321  0.535  0.725  1.0
  Na  Na3  1  0.341  0.034  0.247  1.0
  Na  Na4  1  0.518  0.015  0.821  1.0
  Na  Na5  1  0.731  0.517  0.923  1.0
  Na  Na6  1  0.806  0.861  0.287  1.0
  Na  Na7  1  0.964  0.520  0.604  1.0
  Mg  Mg8  1  0.721  0.086  0.571  1.0
  V  V9  1  0.505  0.566  0.346  1.0
  V  V10  1  0.998  0.009  0.980  1.0
  O  O11  1  0.145  0.261  0.902  1.0
  O  O12  1  0.079  0.788  0.309  1.0
  O  O13  1  0.374  0.751  0.026  1.0
  O  O14  1  0.375  0.312  0.497  1.0
  O  O15  1  0.562  0.808  0.542  1.0
  O  O16  1  0.689  0.436  0.329  1.0
  O  O17  1  0.914  0.888  0.684  1.0
  O  O18  1  0.787  0.132  0.910  1.0
[/CIF]
.