data_Be2TlHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.31
_cell_length_b   3.31
_cell_length_c   6.61
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be2TlHg
_chemical_formula_sum   'Be2 Tl1 Hg1'
_cell_volume   72.23
_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
  Be  Be0  1  0.65  0.65  0.4  1.0
  Be  Be1  1  0.65  0.65  0.21  1.0
  Tl  Tl3  1  0.0  0.0  0.31  1.0
  Hg  Hg2  1  0.0  0.0  0.0  1.0

data_Be2TlHg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.67
_cell_length_b   4.67
_cell_length_c   6.61
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Be2TlHg
_chemical_formula_sum   'Be4 Tl2 Hg2'
_cell_volume   144.46
_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
  Be  Be0  2  0.15  0.5  0.21  1.0
  Be  Be1  2  0.15  0.5  0.4  1.0
  Tl  Tl2  2  0.0  0.0  0.31  1.0
  Hg  Hg3  2  0.0  0.0  0.0  1.0

Be Be Tl Hg
Be2HgTl is Indium-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Be2HgTl clusters. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 1-coordinate geometry to one Be(2) and one Tl(1) atom. The Be(1)-Be(2) bond length is 1.21 Å. The Be(1)-Tl(1) bond length is 1.73 Å. In the second Be site, Be(2) is bonded in a 3-coordinate geometry to one Be(1), one Hg(1), and one Tl(1) atom. The Be(2)-Hg(1) bond length is 2.16 Å. The Be(2)-Tl(1) bond length is 1.73 Å. Hg(1) is bonded in a 2-coordinate geometry to one Be(2) and one Tl(1) atom. The Hg(1)-Tl(1) bond length is 2.02 Å. Tl(1) is bonded in a 3-coordinate geometry to one Be(1), one Be(2), and one Hg(1) atom.