data_Pm
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.44
_cell_length_b   5.44
_cell_length_c   5.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Pm
_chemical_formula_sum   Pm4
_cell_volume   142.41
_cell_formula_units_Z   4
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
  Pm  Pm0  1  0.0  0.0  0.39  1.0
  Pm  Pm1  1  0.0  0.14  0.39  1.0
  Pm  Pm2  1  0.0  0.0  0.17  1.0
  Pm  Pm3  1  0.72  0.57  0.17  1.0

data_Pm
_symmetry_space_group_name_H-M   P1
_cell_length_a   5.44
_cell_length_b   5.44
_cell_length_c   5.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Pm
_chemical_formula_sum   Pm4
_cell_volume   142.41
_cell_formula_units_Z   4
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
  Pm  Pm0  1  0.0  0.0  0.17  1.0
  Pm  Pm1  1  0.0  0.0  0.39  1.0
  Pm  Pm2  1  0.0  0.14  0.39  1.0
  Pm  Pm3  1  0.72  0.57  0.17  1.0

Pm Pm Pm Pm
Pm Pm Pm Pm 0 1 o o o 0 2 o o o 0 3 - - o 1 2 o o o 2 3 - - o 
Pm is Hg_xSn structured and crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one Pm cluster. There are four inequivalent Pm sites. In the first Pm site, Pm(1) is bonded in an L-shaped geometry to one Pm(2) and one Pm(3) atom. The Pm(1)-Pm(2) bond length is 0.77 Å. The Pm(1)-Pm(3) bond length is 1.23 Å. In the second Pm site, Pm(2) is bonded in a distorted single-bond geometry to one Pm(1) atom. In the third Pm site, Pm(3) is bonded in a distorted single-bond geometry to one Pm(1) and one Pm(4) atom. The Pm(3)-Pm(4) bond length is 2.05 Å. In the fourth Pm site, Pm(4) is bonded in a 1-coordinate geometry to one Pm(3) atom.