data_Ba3Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.27
_cell_length_b   8.27
_cell_length_c   6.7
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   118.55
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba3Mg
_chemical_formula_sum   'Ba6 Mg2'
_cell_volume   402.71
_cell_formula_units_Z   2
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
  Ba  Ba0  1  0.23  0.27  0.67  1.0
  Ba  Ba1  1  0.46  0.83  0.67  1.0
  Ba  Ba2  1  0.99  0.83  0.67  1.0
  Ba  Ba3  1  0.23  0.73  0.02  1.0
  Ba  Ba4  1  0.99  0.17  0.02  1.0
  Ba  Ba5  1  0.46  0.17  0.02  1.0
  Mg  Mg6  1  0.23  0.21  0.67  1.0
  Mg  Mg7  1  0.23  0.79  0.02  1.0

data_Ba3Mg
_symmetry_space_group_name_H-M   P-1
_cell_length_a   6.7
_cell_length_b   8.27
_cell_length_c   8.27
_cell_angle_alpha   118.55
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Ba3Mg
_chemical_formula_sum   'Ba6 Mg2'
_cell_volume   402.71
_cell_formula_units_Z   2
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
  Ba  Ba0  2  0.33  0.0  0.27  1.0
  Ba  Ba1  2  0.33  0.24  0.83  1.0
  Ba  Ba2  2  0.33  0.76  0.83  1.0
  Mg  Mg3  2  0.33  0.0  0.21  1.0

Ba Ba Ba Ba Ba Ba Mg Mg
Ba Ba Ba Ba Ba Ba Mg Mg 0 6 o o o 0 2 - - o 0 4 - o + 0 5 o o + 1 7 o o + 1 3 o o + 2 7 + o + 2 3 + o + 2 6 + + o 3 7 o o o 3 5 o + o 4 6 + o - 5 7 o - o 5 6 o o - 
Ba3Mg crystallizes in the triclinic P-1 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a single-bond geometry to three equivalent Ba(2) and one Mg(1) atom. There are a spread of Ba(1)-Ba(2) bond distances ranging from 2.90-4.68 Å. The Ba(1)-Mg(1) bond length is 0.50 Å. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one Ba(2), three equivalent Ba(1), three equivalent Ba(3), and one Mg(1) atom. The Ba(2)-Ba(2) bond length is 4.56 Å. There are a spread of Ba(2)-Ba(3) bond distances ranging from 3.66-4.38 Å. The Ba(2)-Mg(1) bond length is 2.96 Å. In the third Ba site, Ba(3) is bonded in a distorted L-shaped geometry to three equivalent Ba(2) and two equivalent Mg(1) atoms. There is one shorter (2.82 Å) and one longer (3.18 Å) Ba(3)-Mg(1) bond length. Mg(1) is bonded in a single-bond geometry to one Ba(1), one Ba(2), and two equivalent Ba(3) atoms.