data_Mg2TaHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.5
_cell_length_b   5.5
_cell_length_c   2.9
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   113.76
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2TaHg
_chemical_formula_sum   'Mg2 Ta1 Hg1'
_cell_volume   80.32
_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  Mg1  1  0.5  0.69  0.45  1.0
  Mg  Mg2  1  0.5  0.31  0.45  1.0
  Ta  Ta3  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.01  0.0  0.0  1.0

data_Mg2TaHg
_symmetry_space_group_name_H-M   P2
_cell_length_a   5.5
_cell_length_b   2.9
_cell_length_c   5.5
_cell_angle_alpha   90.0
_cell_angle_beta   113.76
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   3
_chemical_formula_structural   Mg2TaHg
_chemical_formula_sum   'Mg2 Ta1 Hg1'
_cell_volume   80.32
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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  2  0.5  0.55  0.31  1.0
  Ta  Ta1  1  0.0  0.0  0.0  1.0
  Hg  Hg2  1  0.0  0.0  0.0  1.0

Mg Mg Ta Hg
Mg Mg Ta Hg 0 1 o o o 2 3 o o o 
Mg2TaHg crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Ta(1) atoms. Both Mg(1)-Mg(1) bond lengths are 2.90 Å. There is one shorter (2.15 Å) and one longer (3.36 Å) Mg(1)-Mg(2) bond length. There is one shorter (2.88 Å) and one longer (3.02 Å) Mg(1)-Ta(1) bond length. In the second Mg site, Mg(2) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and two equivalent Hg(1) atoms. There is one shorter (2.88 Å) and one longer (3.02 Å) Mg(2)-Hg(1) bond length. Ta(1) is bonded in a single-bond geometry to two equivalent Mg(1) and one Hg(1) atom. The Ta(1)-Hg(1) bond length is 0.04 Å. Hg(1) is bonded in a single-bond geometry to two equivalent Mg(2) and one Ta(1) atom.