data_CuNi2Hg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.87
_cell_length_b   2.87
_cell_length_c   6.55
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   91.56
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CuNi2Hg
_chemical_formula_sum   'Cu1 Ni2 Hg1'
_cell_volume   54.05
_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
  Cu  Cu0  1  0.0  0.0  0.0  1.0
  Ni  Ni2  1  0.0  0.0  0.26  1.0
  Ni  Ni3  1  0.0  0.0  0.59  1.0
  Hg  Hg1  1  0.0  0.0  0.96  1.0

data_CuNi2Hg
_symmetry_space_group_name_H-M   P4mm
_cell_length_a   2.87
_cell_length_b   2.87
_cell_length_c   6.55
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   99
_chemical_formula_structural   CuNi2Hg
_chemical_formula_sum   'Cu1 Ni2 Hg1'
_cell_volume   54.07
_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
  Cu  Cu0  1  0.0  0.0  0.0  1.0
  Ni  Ni1  1  0.0  0.0  0.26  1.0
  Ni  Ni2  1  0.0  0.0  0.59  1.0
  Hg  Hg3  1  0.0  0.0  0.96  1.0

Cu Ni Ni Hg
Ni2CuHg crystallizes in the monoclinic Pm space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 6-coordinate geometry to one Ni(2), four equivalent Ni(1), and one Cu(1) atom. The Ni(1)-Ni(2) bond length is 2.17 Å. All Ni(1)-Ni(1) bond lengths are 2.87 Å. The Ni(1)-Cu(1) bond length is 1.70 Å. In the second Ni site, Ni(2) is bonded to one Ni(1), four equivalent Ni(2), and one Hg(1) atom to form a mixture of distorted corner and edge-sharing NiNi5Hg octahedra. The corner-sharing octahedra are not tilted. All Ni(2)-Ni(2) bond lengths are 2.87 Å. The Ni(2)-Hg(1) bond length is 2.41 Å. Cu(1) is bonded in a single-bond geometry to one Ni(1) and one Hg(1) atom. The Cu(1)-Hg(1) bond length is 0.26 Å. Hg(1) is bonded in a single-bond geometry to one Ni(2) and one Cu(1) atom.