data_Sr4CaHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.6
_cell_length_b   7.6
_cell_length_c   7.6
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sr4CaHg
_chemical_formula_sum   'Sr4 Ca1 Hg1'
_cell_volume   310.11
_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
  Sr  Sr2  1  0.03  0.03  0.72  1.0
  Sr  Sr3  1  0.03  0.72  0.03  1.0
  Sr  Sr4  1  0.72  0.03  0.03  1.0
  Sr  Sr5  1  0.72  0.72  0.72  1.0
  Ca  Ca0  1  0.0  0.0  0.0  1.0
  Hg  Hg1  1  0.69  0.69  0.69  1.0

data_Sr4CaHg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   7.6
_cell_length_b   7.6
_cell_length_c   18.61
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Sr4CaHg
_chemical_formula_sum   'Sr12 Ca3 Hg3'
_cell_volume   930.33
_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
  Sr  Sr0  9  0.21  0.1  0.08  1.0
  Sr  Sr1  3  0.0  0.0  0.28  1.0
  Ca  Ca2  3  0.0  0.0  0.0  1.0
  Hg  Hg3  3  0.0  0.0  0.31  1.0

Sr Sr Sr Sr Ca Hg
Sr Sr Sr Sr Ca Hg 0 4 o o + 0 1 o - + 0 2 - o + 1 2 - + o 1 4 o + o 2 4 + o o 3 5 o o o 
Sr3CaSrHg is diamond structured and crystallizes in the trigonal R3m space group. The structure is zero-dimensional and consists of three mercury;strontium molecules and three Sr3Ca clusters. In each Sr3Ca cluster, Sr(1) is bonded in a distorted single-bond geometry to one Ca(1) atom. The Sr(1)-Ca(1) bond length is 1.96 Å. Ca(1) is bonded in a 3-coordinate geometry to three equivalent Sr(1) atoms.