data_BeSnHg2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.13
_cell_length_b   3.13
_cell_length_c   8.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BeSnHg2
_chemical_formula_sum   'Be1 Sn1 Hg2'
_cell_volume   83.81
_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
  Sn  Sn3  1  0.0  0.0  0.28  1.0
  Hg  Hg1  1  0.56  0.56  0.6  1.0
  Hg  Hg2  1  0.56  0.56  0.96  1.0

data_BeSnHg2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.43
_cell_length_b   4.43
_cell_length_c   8.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BeSnHg2
_chemical_formula_sum   'Be2 Sn2 Hg4'
_cell_volume   167.62
_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
  Sn  Sn1  2  0.0  0.0  0.28  1.0
  Hg  Hg2  2  0.06  0.5  0.6  1.0
  Hg  Hg3  2  0.06  0.5  0.96  1.0

Be Sn Hg Hg
Be Sn Hg Hg 0 3 - - - 0 3 - o - 0 3 o - - 0 3 o o - 0 1 o o o 1 3 - - - 1 2 - - o 1 2 o o o 1 2 o - o 1 2 - o o 1 1 + o o 1 1 o + o 2 2 + o o 2 2 o + o 2 3 o o o 
BeHg2Sn crystallizes in the monoclinic Cm space group. Be(1) is bonded to four equivalent Hg(2) and one Sn(1) atom to form distorted BeSnHg4 square pyramids that share corners with five equivalent Hg(1)SnHg5 octahedra, corners with four equivalent Be(1)SnHg4 square pyramids, and edges with four equivalent Be(1)SnHg4 square pyramids. The corner-sharing octahedral tilt angles range from 35-81°. There are a spread of Be(1)-Hg(2) bond distances ranging from 1.96-2.53 Å. The Be(1)-Sn(1) bond length is 2.39 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to one Hg(2), four equivalent Hg(1), and one Sn(1) atom to form distorted HgSnHg5 octahedra that share corners with four equivalent Hg(1)SnHg5 octahedra, corners with five equivalent Be(1)SnHg4 square pyramids, and edges with four equivalent Hg(1)SnHg5 octahedra. The corner-sharing octahedra are not tilted. The Hg(1)-Hg(2) bond length is 3.01 Å. All Hg(1)-Hg(1) bond lengths are 3.13 Å. The Hg(1)-Sn(1) bond length is 3.38 Å. In the second Hg site, Hg(2) is bonded in a 4-coordinate geometry to four equivalent Be(1) and one Hg(1) atom. Sn(1) is bonded in a single-bond geometry to one Be(1) and one Hg(1) atom.