data_Cd2SiHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.99
_cell_length_b   4.99
_cell_length_c   4.99
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Cd2SiHg
_chemical_formula_sum   'Cd2 Si1 Hg1'
_cell_volume   87.76
_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
  Cd  Cd0  1  0.29  0.29  0.29  1.0
  Cd  Cd1  1  0.76  0.76  0.76  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0
  Hg  Hg2  1  0.53  0.53  0.53  1.0

data_Cd2SiHg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.99
_cell_length_b   4.99
_cell_length_c   12.22
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Cd2SiHg
_chemical_formula_sum   'Cd6 Si3 Hg3'
_cell_volume   263.29
_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
  Cd  Cd0  3  0.0  0.0  0.24  1.0
  Cd  Cd1  3  0.0  0.0  0.71  1.0
  Si  Si2  3  0.0  0.0  0.0  1.0
  Hg  Hg3  3  0.0  0.0  0.47  1.0

Cd Cd Si Hg
HgCd2Si is Heusler structured and crystallizes in the trigonal R3m space group. Hg(1) is bonded in a body-centered cubic geometry to four equivalent Cd(1) and four equivalent Cd(2) atoms. There is one shorter (2.89 Å) and three longer (3.11 Å) Hg(1)-Cd(1) bond lengths. There is one shorter (2.89 Å) and three longer (3.11 Å) Hg(1)-Cd(2) bond lengths. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 7-coordinate geometry to four equivalent Hg(1) and three equivalent Si(1) atoms. All Cd(1)-Si(1) bond lengths are 2.93 Å. In the second Cd site, Cd(2) is bonded in a distorted body-centered cubic geometry to four equivalent Hg(1) and four equivalent Si(1) atoms. There is one shorter (2.89 Å) and three longer (3.11 Å) Cd(2)-Si(1) bond lengths. Si(1) is bonded to three equivalent Cd(1) and four equivalent Cd(2) atoms to form a mixture of distorted edge and corner-sharing SiCd7 hexagonal pyramids.