data_MgTlCdHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   5.18
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgTlCdHg
_chemical_formula_sum   'Mg1 Tl1 Cd1 Hg1'
_cell_volume   98.06
_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
  Mg  Mg2  1  0.0  0.0  0.0  1.0
  Tl  Tl3  1  0.49  0.49  0.49  1.0
  Cd  Cd0  1  0.66  0.66  0.66  1.0
  Hg  Hg1  1  0.83  0.83  0.83  1.0

data_MgTlCdHg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   12.68
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgTlCdHg
_chemical_formula_sum   'Mg3 Tl3 Cd3 Hg3'
_cell_volume   294.18
_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
  Mg  Mg0  3  0.0  0.0  0.0  1.0
  Tl  Tl1  3  0.0  0.0  0.51  1.0
  Cd  Cd2  3  0.0  0.0  0.34  1.0
  Hg  Hg3  3  0.0  0.0  0.17  1.0

Mg Tl Cd Hg
Mg Tl Cd Hg 0 3 - - - 1 2 o o o 2 3 o o o 
MgHgCdTl crystallizes in the trigonal R3m space group. Mg(1) is bonded in a distorted single-bond geometry to one Hg(1) and three equivalent Cd(1) atoms. The Mg(1)-Hg(1) bond length is 2.16 Å. All Mg(1)-Cd(1) bond lengths are 2.99 Å. Hg(1) is bonded to one Mg(1), one Cd(1), and three equivalent Tl(1) atoms to form distorted HgMgTl3Cd trigonal bipyramids that share corners with six equivalent Hg(1)MgTl3Cd trigonal bipyramids,  a cornercorner with one Tl(1)CdHg3 trigonal pyramid, and edges with three equivalent Cd(1)Mg3TlHg trigonal bipyramids. The Hg(1)-Cd(1) bond length is 2.16 Å. All Hg(1)-Tl(1) bond lengths are 2.99 Å. Cd(1) is bonded to three equivalent Mg(1), one Hg(1), and one Tl(1) atom to form distorted CdMg3TlHg trigonal bipyramids that share corners with six equivalent Cd(1)Mg3TlHg trigonal bipyramids, corners with three equivalent Tl(1)CdHg3 trigonal pyramids, and edges with three equivalent Hg(1)MgTl3Cd trigonal bipyramids. The Cd(1)-Tl(1) bond length is 2.16 Å. Tl(1) is bonded to three equivalent Hg(1) and one Cd(1) atom to form distorted TlCdHg3 trigonal pyramids that share  a cornercorner with one Hg(1)MgTl3Cd trigonal bipyramid, corners with three equivalent Cd(1)Mg3TlHg trigonal bipyramids, and corners with six equivalent Tl(1)CdHg3 trigonal pyramids.