data_Mg3Pb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.5
_cell_length_b   9.09
_cell_length_c   6.43
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg3Pb
_chemical_formula_sum   'Mg12 Pb4'
_cell_volume   380.14
_cell_formula_units_Z   4
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  0.07  0.27  0.36  1.0
  Mg  Mg1  1  0.63  0.07  0.53  1.0
  Mg  Mg2  1  0.63  0.57  0.53  1.0
  Mg  Mg3  1  0.61  0.52  0.75  1.0
  Mg  Mg4  1  0.61  0.02  0.75  1.0
  Mg  Mg5  1  0.18  0.82  0.14  1.0
  Mg  Mg6  1  0.32  0.27  0.29  1.0
  Mg  Mg7  1  0.88  0.07  0.69  1.0
  Mg  Mg8  1  0.88  0.57  0.69  1.0
  Mg  Mg9  1  0.86  0.52  0.9  1.0
  Mg  Mg10  1  0.86  0.02  0.9  1.0
  Mg  Mg11  1  0.43  0.82  0.08  1.0
  Pb  Pb12  1  0.38  0.82  0.3  1.0
  Pb  Pb13  1  0.36  0.27  0.08  1.0
  Pb  Pb14  1  0.13  0.82  0.35  1.0
  Pb  Pb15  1  0.11  0.27  0.14  1.0

data_Mg3Pb
_symmetry_space_group_name_H-M   P-1
_cell_length_a   6.43
_cell_length_b   6.5
_cell_length_c   9.09
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Mg3Pb
_chemical_formula_sum   'Mg12 Pb4'
_cell_volume   380.14
_cell_formula_units_Z   4
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  0.08  0.07  0.23  1.0
  Mg  Mg1  2  0.14  0.82  0.23  1.0
  Mg  Mg2  2  0.31  0.39  0.02  1.0
  Mg  Mg3  2  0.31  0.39  0.52  1.0
  Mg  Mg4  2  0.47  0.63  0.02  1.0
  Mg  Mg5  2  0.47  0.63  0.52  1.0
  Pb  Pb6  2  0.08  0.13  0.77  1.0
  Pb  Pb7  2  0.14  0.89  0.77  1.0

Mg Mg Mg Mg Mg Mg Mg Mg Mg Mg Mg Mg Pb Pb Pb Pb
Mg3Pb crystallizes in the triclinic P-1 space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to one Mg(5) and one Pb(1) atom. The Mg(1)-Mg(5) bond length is 3.06 Å. The Mg(1)-Pb(1) bond length is 1.44 Å. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to one Mg(6), two equivalent Mg(5), and one Pb(1) atom. The Mg(2)-Mg(6) bond length is 3.15 Å. There is one shorter (1.47 Å) and one longer (1.90 Å) Mg(2)-Mg(5) bond length. The Mg(2)-Pb(1) bond length is 3.19 Å. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent Mg(4) and one Pb(1) atom. There is one shorter (1.46 Å) and one longer (1.90 Å) Mg(3)-Mg(4) bond length. The Mg(3)-Pb(1) bond length is 3.19 Å. In the fourth Mg site, Mg(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(4), two equivalent Mg(3), and one Pb(2) atom. The Mg(4)-Mg(4) bond length is 1.84 Å. The Mg(4)-Pb(2) bond length is 3.52 Å. In the fifth Mg site, Mg(5) is bonded in a 5-coordinate geometry to one Mg(1), one Mg(5), two equivalent Mg(2), and one Pb(2) atom. The Mg(5)-Mg(5) bond length is 1.85 Å. The Mg(5)-Pb(2) bond length is 3.52 Å. In the sixth Mg site, Mg(6) is bonded in a 2-coordinate geometry to one Mg(2), one Pb(1), and one Pb(2) atom. The Mg(6)-Pb(1) bond length is 1.66 Å. The Mg(6)-Pb(2) bond length is 1.41 Å. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 5-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(6), and one Pb(2) atom. The Pb(1)-Pb(2) bond length is 1.65 Å. In the second Pb site, Pb(2) is bonded in a single-bond geometry to one Mg(4), one Mg(5), one Mg(6), and one Pb(1) atom.