data_CaSiSnHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.19
_cell_length_b   5.19
_cell_length_c   5.19
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaSiSnHg
_chemical_formula_sum   'Ca1 Si1 Sn1 Hg1'
_cell_volume   98.69
_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
  Ca  Ca0  1  0.5  0.5  0.5  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0
  Sn  Sn3  1  0.67  0.67  0.67  1.0
  Hg  Hg1  1  0.83  0.83  0.83  1.0

data_CaSiSnHg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.19
_cell_length_b   5.19
_cell_length_c   12.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CaSiSnHg
_chemical_formula_sum   'Ca3 Si3 Sn3 Hg3'
_cell_volume   296.08
_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
  Ca  Ca0  3  0.0  0.0  0.5  1.0
  Si  Si1  3  0.0  0.0  0.0  1.0
  Sn  Sn2  3  0.0  0.0  0.33  1.0
  Hg  Hg3  3  0.0  0.0  0.17  1.0

Ca Si Sn Hg
Ca Si Sn Hg 0 2 o o o 1 3 - - - 2 3 o o o 
CaHgSnSi crystallizes in the trigonal R3m space group. Ca(1) is bonded to three equivalent Hg(1) and one Sn(1) atom to form distorted CaSnHg3 trigonal pyramids that share  a cornercorner with one Hg(1)Ca3SiSn trigonal bipyramid and corners with six equivalent Ca(1)SnHg3 trigonal pyramids. All Ca(1)-Hg(1) bond lengths are 2.99 Å. The Ca(1)-Sn(1) bond length is 2.11 Å. Hg(1) is bonded to three equivalent Ca(1), one Sn(1), and one Si(1) atom to form HgCa3SiSn trigonal bipyramids that share corners with six equivalent Hg(1)Ca3SiSn trigonal bipyramids and  a cornercorner with one Ca(1)SnHg3 trigonal pyramid. The Hg(1)-Sn(1) bond length is 2.11 Å. The Hg(1)-Si(1) bond length is 2.11 Å. Sn(1) is bonded in a 2-coordinate geometry to one Ca(1) and one Hg(1) atom. Si(1) is bonded in a distorted single-bond geometry to one Hg(1) atom.