data_BeHg2Sb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   5.04
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BeHg2Sb
_chemical_formula_sum   'Be1 Hg2 Sb1'
_cell_volume   90.35
_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
  Hg  Hg1  1  0.34  0.34  0.34  1.0
  Hg  Hg2  1  0.78  0.78  0.78  1.0
  Sb  Sb3  1  0.56  0.56  0.56  1.0

data_BeHg2Sb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   12.34
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   BeHg2Sb
_chemical_formula_sum   'Be3 Hg6 Sb3'
_cell_volume   271.04
_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
  Be  Be0  3  0.0  0.0  0.0  1.0
  Hg  Hg1  3  0.0  0.0  0.22  1.0
  Hg  Hg2  3  0.0  0.0  0.66  1.0
  Sb  Sb3  3  0.0  0.0  0.44  1.0

Be Hg Hg Sb
Be Hg Hg Sb 0 2 - - - 0 2 - - o 0 2 o - - 0 2 - o - 0 3 - - o 0 3 - o - 0 3 o - - 0 1 - o o 0 1 o - o 0 1 o o - 1 3 o - o 1 3 - o o 1 3 o o - 1 3 o o o 1 2 - o o 1 2 o - o 1 2 o o - 2 3 o o o 2 3 o o + 2 3 + o o 2 3 o + o 
BeHg2Sb is Heusler structured and crystallizes in the trigonal R3m space group. Be(1) is bonded to one Hg(2) and three equivalent Hg(1) atoms to form corner-sharing BeHg4 trigonal pyramids. The Be(1)-Hg(2) bond length is 2.71 Å. All Be(1)-Hg(1) bond lengths are 2.91 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to three equivalent Be(1) and one Sb(1) atom to form distorted corner-sharing HgBe3Sb trigonal pyramids. The Hg(1)-Sb(1) bond length is 2.71 Å. In the second Hg site, Hg(2) is bonded in a 2-coordinate geometry to one Be(1) and one Sb(1) atom. The Hg(2)-Sb(1) bond length is 2.71 Å. Sb(1) is bonded in a 2-coordinate geometry to one Hg(1) and one Hg(2) atom.