data_BeCu2Hg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.85
_cell_length_b   3.85
_cell_length_c   3.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BeCu2Hg
_chemical_formula_sum   'Be1 Cu2 Hg1'
_cell_volume   54.29
_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  0.0  0.0  0.0  1.0
  Cu  Cu1  1  0.0  0.92  0.83  1.0
  Cu  Cu2  1  0.92  0.0  0.83  1.0
  Hg  Hg3  1  0.92  0.92  0.0  1.0

data_BeCu2Hg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.44
_cell_length_b   5.44
_cell_length_c   3.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BeCu2Hg
_chemical_formula_sum   'Be2 Cu4 Hg2'
_cell_volume   108.58
_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  0.0  0.0  0.0  1.0
  Cu  Cu1  4  0.46  0.46  0.83  1.0
  Hg  Hg2  2  0.42  0.5  -0.0  1.0

Be Cu Cu Hg
Be Cu Cu Hg 0 3 - - o 1 2 - + o 
BeCu2Hg is alpha Po structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two BeCu2Hg clusters. Be(1) is bonded in a distorted single-bond geometry to two equivalent Cu(1) and one Hg(1) atom. Both Be(1)-Cu(1) bond lengths are 0.68 Å. The Be(1)-Hg(1) bond length is 0.41 Å. Cu(1) is bonded in a 3-coordinate geometry to one Be(1), one Cu(1), and one Hg(1) atom. The Cu(1)-Cu(1) bond length is 0.41 Å. The Cu(1)-Hg(1) bond length is 0.68 Å. Hg(1) is bonded in a single-bond geometry to one Be(1) and two equivalent Cu(1) atoms.