data_Na2AcHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.43
_cell_length_b   5.43
_cell_length_c   5.43
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2AcHg
_chemical_formula_sum   'Na2 Ac1 Hg1'
_cell_volume   113.5
_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  Na2  1  0.76  0.76  0.76  1.0
  Na  Na3  1  0.92  0.92  0.92  1.0
  Ac  Ac0  1  0.84  0.84  0.84  1.0
  Hg  Hg1  1  0.0  0.0  0.0  1.0

data_Na2AcHg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.43
_cell_length_b   5.43
_cell_length_c   13.31
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na2AcHg
_chemical_formula_sum   'Na6 Ac3 Hg3'
_cell_volume   340.51
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.08  1.0
  Na  Na1  3  0.0  0.0  0.24  1.0
  Ac  Ac2  3  0.0  0.0  0.16  1.0
  Hg  Hg3  3  0.0  0.0  0.0  1.0

Na Na Ac Hg
Na Na Ac Hg 0 2 o o o 1 2 o o o 1 3 + + + 
Na2AcHg crystallizes in the trigonal R3m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one Ac(1) and three equivalent Hg(1) atoms to form distorted corner-sharing NaAcHg3 tetrahedra. The Na(1)-Ac(1) bond length is 1.05 Å. All Na(1)-Hg(1) bond lengths are 3.40 Å. In the second Na site, Na(2) is bonded in a linear geometry to one Ac(1) and one Hg(1) atom. The Na(2)-Ac(1) bond length is 1.05 Å. The Na(2)-Hg(1) bond length is 1.05 Å. Ac(1) is bonded in a linear geometry to one Na(1) and one Na(2) atom. Hg(1) is bonded in a single-bond geometry to one Na(2) and three equivalent Na(1) atoms.