data_Cr2CuHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.99
_cell_length_b   2.99
_cell_length_c   6.43
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Cr2CuHg
_chemical_formula_sum   'Cr2 Cu1 Hg1'
_cell_volume   57.51
_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
  Cr  Cr0  1  0.0  0.0  0.4  1.0
  Cr  Cr1  1  0.49  0.49  0.43  1.0
  Cu  Cu2  1  0.0  0.0  0.01  1.0
  Hg  Hg3  1  0.49  0.49  0.8  1.0

data_Cr2CuHg
_symmetry_space_group_name_H-M   P4mm
_cell_length_a   2.99
_cell_length_b   2.99
_cell_length_c   6.43
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   99
_chemical_formula_structural   Cr2CuHg
_chemical_formula_sum   'Cr2 Cu1 Hg1'
_cell_volume   57.51
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x, z'
  3  '-x, -y, z'
  4  'y, -x, z'
  5  '-x, y, z'
  6  'y, x, z'
  7  'x, -y, z'
  8  '-y, -x, 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
  Cr  Cr0  1  0.0  0.0  0.4  1.0
  Cr  Cr1  1  0.5  0.5  0.43  1.0
  Cu  Cu2  1  0.0  0.0  0.01  1.0
  Hg  Hg3  1  0.5  0.5  0.8  1.0

Cr Cr Cu Hg
Cr Cr Cu Hg 0 1 - - o 0 1 - o o 0 1 o - o 0 1 o o o 0 2 o o o 1 3 o o o 2 3 - - - 2 3 - o - 2 3 o - - 2 3 o o - 2 2 + o o 2 2 o + o 3 3 + o o 3 3 o + o 
Cr2CuHg crystallizes in the monoclinic Cm space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to four equivalent Cr(2) and one Cu(1) atom to form a mixture of corner and edge-sharing CrCr4Cu square pyramids. There are a spread of Cr(1)-Cr(2) bond distances ranging from 2.10-2.14 Å. The Cr(1)-Cu(1) bond length is 2.51 Å. In the second Cr site, Cr(2) is bonded to four equivalent Cr(1) and one Hg(1) atom to form a mixture of distorted corner and edge-sharing CrCr4Hg square pyramids. The Cr(2)-Hg(1) bond length is 2.37 Å. Cu(1) is bonded in a 5-coordinate geometry to one Cr(1) and four equivalent Hg(1) atoms. There are a spread of Cu(1)-Hg(1) bond distances ranging from 2.49-2.53 Å. Hg(1) is bonded in a 5-coordinate geometry to one Cr(2) and four equivalent Cu(1) atoms.