data_Mg2HgAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.89
_cell_length_b   4.03
_cell_length_c   5.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2HgAs
_chemical_formula_sum   'Mg2 Hg1 As1'
_cell_volume   88.67
_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
  Mg  Mg2  1  0.0  0.0  0.35  1.0
  Mg  Mg3  1  0.94  0.02  0.79  1.0
  Hg  Hg1  1  0.94  0.02  0.6  1.0
  As  As0  1  0.0  0.0  0.41  1.0

data_Mg2HgAs
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.89
_cell_length_b   4.03
_cell_length_c   5.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2HgAs
_chemical_formula_sum   'Mg2 Hg1 As1'
_cell_volume   88.67
_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
  Mg  Mg0  1  0.0  0.0  0.35  1.0
  Mg  Mg1  1  0.94  0.02  0.79  1.0
  Hg  Hg2  1  0.94  0.02  0.6  1.0
  As  As3  1  0.0  0.0  0.41  1.0

Mg Mg Hg As
Mg Mg Hg As 0 3 o o o 1 2 o o o 2 3 + o o 
Mg2HgAs is Indium-like structured and crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one Mg2HgAs cluster. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to one As(1) atom. The Mg(1)-As(1) bond length is 0.38 Å. In the second Mg site, Mg(2) is bonded in a single-bond geometry to one Hg(1) atom. The Mg(2)-Hg(1) bond length is 1.11 Å. Hg(1) is bonded in a linear geometry to one Mg(2) and one As(1) atom. The Hg(1)-As(1) bond length is 1.06 Å. As(1) is bonded in a distorted linear geometry to one Mg(1) and one Hg(1) atom.