data_Al2Hg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.48
_cell_length_b   6.48
_cell_length_c   6.48
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Al2Hg
_chemical_formula_sum   'Al8 Hg4'
_cell_volume   272.72
_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
  Al  Al0  1  0.78  0.02  0.7  1.0
  Al  Al1  1  0.7  0.46  0.78  1.0
  Al  Al2  1  0.02  0.7  0.78  1.0
  Al  Al3  1  0.46  0.78  0.7  1.0
  Al  Al4  1  0.7  0.78  0.02  1.0
  Al  Al5  1  0.78  0.7  0.46  1.0
  Al  Al6  1  0.46  0.46  0.46  1.0
  Al  Al7  1  0.02  0.02  0.02  1.0
  Hg  Hg8  1  0.24  0.0  0.24  1.0
  Hg  Hg9  1  0.0  0.24  0.24  1.0
  Hg  Hg10  1  0.0  0.0  0.0  1.0
  Hg  Hg11  1  0.24  0.24  0.0  1.0

data_Al2Hg
_symmetry_space_group_name_H-M   R3
_cell_length_a   9.17
_cell_length_b   9.17
_cell_length_c   11.23
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   146
_chemical_formula_structural   Al2Hg
_chemical_formula_sum   'Al24 Hg12'
_cell_volume   818.15
_cell_formula_units_Z   12
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  'x+1/3, y+2/3, z+2/3'
  5  '-y+1/3, x-y+2/3, z+2/3'
  6  '-x+y+1/3, -x+2/3, z+2/3'
  7  'x+2/3, y+1/3, z+1/3'
  8  '-y+2/3, x-y+1/3, z+1/3'
  9  '-x+y+2/3, -x+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
  Al  Al0  9  0.06  0.87  0.65  1.0
  Al  Al1  9  0.19  0.06  0.84  1.0
  Al  Al2  3  0.0  0.0  0.02  1.0
  Al  Al3  3  0.0  0.0  0.46  1.0
  Hg  Hg4  9  0.08  0.92  0.16  1.0
  Hg  Hg5  3  0.0  0.0  0.0  1.0

Al Al Al Al Al Al Al Al Hg Hg Hg Hg
Al Al Al Al Al Al Al Al Hg Hg Hg Hg 0 4 o - + 0 3 o - o 0 1 o o o 0 5 o - o 0 10 + o + 0 2 + - o 0 7 + o + 1 6 o o o 1 3 o o o 1 5 o o o 1 2 + o o 1 4 o o + 2 5 - o o 2 10 o + + 2 4 - o + 2 3 o o o 2 7 o + + 3 6 o o o 3 5 o o o 3 4 o o + 4 5 o o o 4 10 + + o 4 7 + + o 5 6 o o o 7 10 o o o 7 8 o o o 7 9 o o o 7 11 o o o 8 10 o o o 8 9 o o o 8 11 o o o 9 10 o o o 9 11 o o o 10 11 o o o 
HgAl2 crystallizes in the trigonal R3 space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a distorted single-bond geometry to one Al(4) atom. The Hg(1)-Al(4) bond length is 2.01 Å. In the second Hg site, Hg(2) is bonded in a single-bond geometry to one Al(4) and three equivalent Al(1) atoms. The Hg(2)-Al(4) bond length is 0.26 Å. All Hg(2)-Al(1) bond lengths are 2.39 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a distorted single-bond geometry to one Hg(2) and three equivalent Al(2) atoms. There are two shorter (2.60 Å) and one longer (2.93 Å) Al(1)-Al(2) bond length. In the second Al site, Al(2) is bonded in a distorted hexagonal planar geometry to one Al(3), two equivalent Al(2), and three equivalent Al(1) atoms. The Al(2)-Al(3) bond length is 2.60 Å. Both Al(2)-Al(2) bond lengths are 2.65 Å. In the third Al site, Al(3) is bonded in a 3-coordinate geometry to three equivalent Al(2) atoms. In the fourth Al site, Al(4) is bonded in a single-bond geometry to one Hg(2) and three equivalent Hg(1) atoms.