data_CaCr2Hg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.1
_cell_length_b   5.1
_cell_length_c   5.1
_cell_angle_alpha   126.09
_cell_angle_beta   126.09
_cell_angle_gamma   79.74
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaCr2Hg
_chemical_formula_sum   'Ca1 Cr2 Hg1'
_cell_volume   83.63
_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  0.0  0.0  0.0  1.0
  Cr  Cr1  1  0.31  0.0  0.96  1.0
  Cr  Cr2  1  0.0  0.31  0.96  1.0
  Hg  Hg3  1  0.0  0.0  0.91  1.0

data_CaCr2Hg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.54
_cell_length_b   6.54
_cell_length_c   5.1
_cell_angle_alpha   90.0
_cell_angle_beta   129.87
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   CaCr2Hg
_chemical_formula_sum   'Ca2 Cr4 Hg2'
_cell_volume   167.26
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.0  1.0
  Cr  Cr1  4  0.34  0.34  0.65  1.0
  Hg  Hg2  2  0.0  0.0  0.91  1.0

Ca Cr Cr Hg
Ca Cr Cr Hg 0 3 o o - 0 1 o o - 0 2 o o - 1 3 o o o 2 3 o o o 
CaCr2Hg is Copper structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two CaCr2Hg clusters. Ca(1) is bonded in a single-bond geometry to one Hg(1) atom. The Ca(1)-Hg(1) bond length is 0.44 Å. Cr(1) is bonded in a single-bond geometry to one Hg(1) atom. The Cr(1)-Hg(1) bond length is 1.47 Å. Hg(1) is bonded in a single-bond geometry to one Ca(1) and two equivalent Cr(1) atoms.