The crystal structure described by Na8Mg(CoO4)2 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(8) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Na(5)O4 tetrahedra,  a cornercorner with one Co(2)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Na(5)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and  an edgeedge with one Co(2)O4 tetrahedra. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and one O(5) atom. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(4), one O(5), one O(6), and one O(7) atom. In the fifth Na site, Na(5) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid,  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, and  an edgeedge with one Na(1)O5 square pyramid. 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(6), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), one O(6), and one O(8) atom. In the eighth Na site, Na(8) is bonded in a distorted rectangular see-saw-like geometry to one O(4), one O(5), one O(6), and one O(7) atom. Mg(1) is bonded to one O(1), one O(3), one O(6), and one O(8) atom to form MgO4 tetrahedra that share corners with three equivalent Na(1)O5 square pyramids,  a cornercorner with one Na(5)O4 tetrahedra,  a cornercorner with one Co(2)O4 tetrahedra, and corners with three equivalent Co(1)O4 tetrahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form CoO4 tetrahedra that share  a cornercorner with one Na(5)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Na(1)O5 square pyramid. In the second Co site, Co(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form CoO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid,  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Na(5)O4 tetrahedra, and  an edgeedge with one Na(1)O5 square pyramid. 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(6), one Na(7), one Mg(1), and one Co(1) atom. In the second O site, O(2) is bonded to one Na(1), one Na(3), one Na(5), one Na(6), one Na(7), and one Co(2) atom to form corner-sharing ONa5Co octahedra. In the third O site, O(3) is bonded in a 7-coordinate geometry to one Na(1), one Na(3), one Na(5), one Na(6), one Na(7), one Mg(1), and one Co(2) atom. 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(4), one Na(5), one Na(8), and one Co(2) atom. In the fifth O site, O(5) is bonded to one Na(2), one Na(3), one Na(4), one Na(8), and one Co(2) atom to form corner-sharing ONa4Co trigonal bipyramids. The corner-sharing octahedral tilt angles range from 44-69°. In the sixth O site, O(6) is bonded in a 7-coordinate geometry to one Na(2), one Na(4), one Na(6), one Na(7), one Na(8), one Mg(1), and one Co(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(2), one Na(4), one Na(5), one Na(8), and one Co(1) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(1), one Na(6), one Na(7), one Mg(1), and one Co(1) atom. is represented by the CIF card [CIF]
data_Na8Mg(CoO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.805
_cell_length_b   5.739
_cell_length_c   9.134
_cell_angle_alpha   68.070
_cell_angle_beta   83.232
_cell_angle_gamma   69.890
_symmetry_Int_Tables_number   1
_cell_volume   265.040
_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  0.974  0.765  0.343  1.0
  Na  Na1  1  0.543  0.403  0.822  1.0
  Na  Na2  1  0.508  0.206  0.450  1.0
  Na  Na3  1  0.430  0.036  0.780  1.0
  Na  Na4  1  0.996  0.239  0.561  1.0
  Na  Na5  1  0.471  0.803  0.159  1.0
  Na  Na6  1  0.903  0.372  0.192  1.0
  Na  Na7  1  0.977  0.627  0.761  1.0
  Mg  Mg8  1  0.355  0.295  0.131  1.0
  Co  Co9  1  0.991  0.010  0.990  1.0
  Co  Co10  1  0.446  0.705  0.492  1.0
  O  O11  1  0.707  0.184  0.093  1.0
  O  O12  1  0.693  0.522  0.379  1.0
  O  O13  1  0.265  0.052  0.339  1.0
  O  O14  1  0.256  0.481  0.578  1.0
  O  O15  1  0.586  0.779  0.634  1.0
  O  O16  1  0.212  0.209  0.973  1.0
  O  O17  1  0.866  0.029  0.811  1.0
  O  O18  1  0.171  0.659  0.117  1.0
[/CIF]
.
The crystal structure described by Na8Mg(CoO4)2 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(8) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Na(5)O4 tetrahedra,  a cornercorner with one Co(2)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Na(5)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and  an edgeedge with one Co(2)O4 tetrahedra. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and one O(5) atom. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(4), one O(5), one O(6), and one O(7) atom. In the fifth Na site, Na(5) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid,  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, and  an edgeedge with one Na(1)O5 square pyramid. 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(6), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), one O(6), and one O(8) atom. In the eighth Na site, Na(8) is bonded in a distorted rectangular see-saw-like geometry to one O(4), one O(5), one O(6), and one O(7) atom. Mg(1) is bonded to one O(1), one O(3), one O(6), and one O(8) atom to form MgO4 tetrahedra that share corners with three equivalent Na(1)O5 square pyramids,  a cornercorner with one Na(5)O4 tetrahedra,  a cornercorner with one Co(2)O4 tetrahedra, and corners with three equivalent Co(1)O4 tetrahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form CoO4 tetrahedra that share  a cornercorner with one Na(5)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Na(1)O5 square pyramid. In the second Co site, Co(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form CoO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid,  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Na(5)O4 tetrahedra, and  an edgeedge with one Na(1)O5 square pyramid. 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(6), one Na(7), one Mg(1), and one Co(1) atom. In the second O site, O(2) is bonded to one Na(1), one Na(3), one Na(5), one Na(6), one Na(7), and one Co(2) atom to form corner-sharing ONa5Co octahedra. In the third O site, O(3) is bonded in a 7-coordinate geometry to one Na(1), one Na(3), one Na(5), one Na(6), one Na(7), one Mg(1), and one Co(2) atom. 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(4), one Na(5), one Na(8), and one Co(2) atom. In the fifth O site, O(5) is bonded to one Na(2), one Na(3), one Na(4), one Na(8), and one Co(2) atom to form corner-sharing ONa4Co trigonal bipyramids. The corner-sharing octahedral tilt angles range from 44-69°. In the sixth O site, O(6) is bonded in a 7-coordinate geometry to one Na(2), one Na(4), one Na(6), one Na(7), one Na(8), one Mg(1), and one Co(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(2), one Na(4), one Na(5), one Na(8), and one Co(1) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(1), one Na(6), one Na(7), one Mg(1), and one Co(1) atom. is represented by the CIF card [CIF]
data_Na8Mg(CoO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.805
_cell_length_b   5.739
_cell_length_c   9.134
_cell_angle_alpha   68.070
_cell_angle_beta   83.232
_cell_angle_gamma   69.890
_symmetry_Int_Tables_number   1
_cell_volume   265.040
_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  0.974  0.765  0.343  1.0
  Na  Na1  1  0.543  0.403  0.822  1.0
  Na  Na2  1  0.508  0.206  0.450  1.0
  Na  Na3  1  0.430  0.036  0.780  1.0
  Na  Na4  1  0.996  0.239  0.561  1.0
  Na  Na5  1  0.471  0.803  0.159  1.0
  Na  Na6  1  0.903  0.372  0.192  1.0
  Na  Na7  1  0.977  0.627  0.761  1.0
  Mg  Mg8  1  0.355  0.295  0.131  1.0
  Co  Co9  1  0.991  0.010  0.990  1.0
  Co  Co10  1  0.446  0.705  0.492  1.0
  O  O11  1  0.707  0.184  0.093  1.0
  O  O12  1  0.693  0.522  0.379  1.0
  O  O13  1  0.265  0.052  0.339  1.0
  O  O14  1  0.256  0.481  0.578  1.0
  O  O15  1  0.586  0.779  0.634  1.0
  O  O16  1  0.212  0.209  0.973  1.0
  O  O17  1  0.866  0.029  0.811  1.0
  O  O18  1  0.171  0.659  0.117  1.0
[/CIF]
.