data_Na8Hg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.99
_cell_length_b   7.99
_cell_length_c   7.99
_cell_angle_alpha   95.73
_cell_angle_beta   95.73
_cell_angle_gamma   143.15
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na8Hg
_chemical_formula_sum   'Na8 Hg1'
_cell_volume   290.37
_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  Na1  1  0.67  0.33  0.53  1.0
  Na  Na2  1  0.33  0.67  0.53  1.0
  Na  Na3  1  0.46  0.0  0.0  1.0
  Na  Na4  1  0.67  0.67  0.53  1.0
  Na  Na5  1  0.0  0.46  0.0  1.0
  Na  Na6  1  0.7  0.7  0.0  1.0
  Na  Na7  1  0.26  0.0  0.0  1.0
  Na  Na8  1  0.0  0.26  0.0  1.0
  Hg  Hg0  1  0.0  0.0  0.0  1.0

data_Na8Hg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.05
_cell_length_b   15.16
_cell_length_c   7.99
_cell_angle_alpha   90.0
_cell_angle_beta   108.42
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na8Hg
_chemical_formula_sum   'Na16 Hg2'
_cell_volume   580.74
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  4  0.03  0.17  0.53  1.0
  Na  Na1  4  0.27  0.73  -0.0  1.0
  Na  Na2  4  0.37  0.63  -0.0  1.0
  Na  Na3  2  0.3  0.0  -0.0  1.0
  Na  Na4  2  0.36  0.5  0.53  1.0
  Hg  Hg5  2  0.0  0.0  0.0  1.0

Na Na Na Na Na Na Na Na Hg
Na Na Na Na Na Na Na Na Hg 0 3 o o o 1 3 o o o 2 6 o o o 4 7 o o o 5 8 + + o 
Na8Hg is Indium-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Na8Hg clusters. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 1-coordinate geometry to one Na(3) atom. The Na(1)-Na(3) bond length is 2.65 Å. In the second Na site, Na(2) is bonded in a distorted single-bond geometry to one Na(5) atom. The Na(2)-Na(5) bond length is 1.57 Å. In the third Na site, Na(3) is bonded in a distorted T-shaped geometry to two equivalent Na(1) and one Hg(1) atom. The Na(3)-Hg(1) bond length is 3.63 Å. In the fourth Na site, Na(4) is bonded in a single-bond geometry to one Hg(1) atom. The Na(4)-Hg(1) bond length is 1.54 Å. In the fifth Na site, Na(5) is bonded in a distorted linear geometry to one Na(2) and one Hg(1) atom. The Na(5)-Hg(1) bond length is 2.10 Å. Hg(1) is bonded in a 3-coordinate geometry to one Na(3), one Na(4), and two equivalent Na(5) atoms.