data_FeNiHg2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.56
_cell_length_b   4.56
_cell_length_c   4.56
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeNiHg2
_chemical_formula_sum   'Fe1 Ni1 Hg2'
_cell_volume   66.98
_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
  Fe  Fe0  1  0.0  0.0  0.0  1.0
  Ni  Ni3  1  0.84  0.84  0.84  1.0
  Hg  Hg1  1  0.22  0.22  0.22  1.0
  Hg  Hg2  1  0.61  0.61  0.61  1.0

data_FeNiHg2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.56
_cell_length_b   4.56
_cell_length_c   11.17
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   FeNiHg2
_chemical_formula_sum   'Fe3 Ni3 Hg6'
_cell_volume   200.95
_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
  Fe  Fe0  3  0.0  0.0  0.0  1.0
  Ni  Ni1  3  0.0  0.0  0.16  1.0
  Hg  Hg2  3  0.0  0.0  0.39  1.0
  Hg  Hg3  3  0.0  0.0  0.78  1.0

Fe Ni Hg Hg
Fe Ni Hg Hg 0 1 - - - 0 2 o o o 0 2 o o - 0 2 - o o 0 2 o - o 0 3 o - - 0 3 - o - 0 3 - - o 1 2 + + o 1 2 + o + 1 2 o + + 1 3 o + o 1 3 + o o 1 3 o o + 1 3 o o o 2 3 - o o 2 3 o - o 2 3 o o - 
FeNiHg2 crystallizes in the trigonal R3m space group. Fe(1) is bonded in a 1-coordinate geometry to one Ni(1), three equivalent Hg(2), and four equivalent Hg(1) atoms. The Fe(1)-Ni(1) bond length is 1.84 Å. All Fe(1)-Hg(2) bond lengths are 2.70 Å. There is one shorter (2.49 Å) and three longer (2.90 Å) Fe(1)-Hg(1) bond lengths. Ni(1) is bonded in a 1-coordinate geometry to one Fe(1), three equivalent Hg(1), and four equivalent Hg(2) atoms. All Ni(1)-Hg(1) bond lengths are 2.70 Å. There is one shorter (2.49 Å) and three longer (2.90 Å) Ni(1)-Hg(2) bond lengths. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a 10-coordinate geometry to four equivalent Fe(1), three equivalent Ni(1), and three equivalent Hg(2) atoms. All Hg(1)-Hg(2) bond lengths are 2.70 Å. In the second Hg site, Hg(2) is bonded in a 10-coordinate geometry to three equivalent Fe(1), four equivalent Ni(1), and three equivalent Hg(1) atoms.