data_NbHgAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.67
_cell_length_b   3.67
_cell_length_c   6.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NbHgAs2
_chemical_formula_sum   'Nb1 Hg1 As2'
_cell_volume   81.65
_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
  Nb  Nb3  1  0.0  0.0  0.1  1.0
  Hg  Hg2  1  0.83  0.83  0.86  1.0
  As  As0  1  0.83  0.83  0.6  1.0
  As  As1  1  0.0  0.0  0.61  1.0

data_NbHgAs2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.19
_cell_length_b   5.19
_cell_length_c   6.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   NbHgAs2
_chemical_formula_sum   'Nb2 Hg2 As4'
_cell_volume   163.3
_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
  Nb  Nb0  2  0.0  0.0  0.1  1.0
  Hg  Hg1  2  0.33  0.5  0.86  1.0
  As  As2  2  0.0  0.0  0.61  1.0
  As  As3  2  0.33  0.5  0.6  1.0

Nb Hg As As
Nb Hg As As 0 1 - - - 1 3 + + o 1 2 o o o 2 3 + + o 
NbHgAs2 crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two NbHgAs2 clusters. Nb(1) is bonded in a single-bond geometry to one Hg(1) atom. The Nb(1)-Hg(1) bond length is 1.72 Å. Hg(1) is bonded in a 3-coordinate geometry to one Nb(1), one As(1), and one As(2) atom. The Hg(1)-As(1) bond length is 1.57 Å. The Hg(1)-As(2) bond length is 1.71 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a distorted L-shaped geometry to one Hg(1) and one As(2) atom. The As(1)-As(2) bond length is 0.87 Å. In the second As site, As(2) is bonded in a 2-coordinate geometry to one Hg(1) and one As(1) atom.