data_HfMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.0
_cell_length_b   6.35
_cell_length_c   6.35
_cell_angle_alpha   119.36
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfMg
_chemical_formula_sum   'Hf4 Mg4'
_cell_volume   175.89
_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
  Hf  Hf0  1  0.75  0.16  0.85  1.0
  Hf  Hf1  1  0.75  0.83  0.33  1.0
  Hf  Hf2  1  0.25  0.84  0.85  1.0
  Hf  Hf3  1  0.25  0.17  0.33  1.0
  Mg  Mg4  1  0.75  0.38  0.27  1.0
  Mg  Mg5  1  0.75  0.05  0.65  1.0
  Mg  Mg6  1  0.25  0.62  0.27  1.0
  Mg  Mg7  1  0.25  0.95  0.65  1.0

data_HfMg
_symmetry_space_group_name_H-M   Pm
_cell_length_a   6.35
_cell_length_b   5.0
_cell_length_c   6.35
_cell_angle_alpha   90.0
_cell_angle_beta   119.36
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   HfMg
_chemical_formula_sum   'Hf4 Mg4'
_cell_volume   175.89
_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
  Hf  Hf0  1  0.16  0.0  0.85  1.0
  Hf  Hf1  1  0.17  0.5  0.33  1.0
  Hf  Hf2  1  0.83  0.0  0.33  1.0
  Hf  Hf3  1  0.84  0.5  0.85  1.0
  Mg  Mg4  1  0.05  0.0  0.65  1.0
  Mg  Mg5  1  0.38  0.0  0.27  1.0
  Mg  Mg6  1  0.62  0.5  0.27  1.0
  Mg  Mg7  1  0.95  0.5  0.65  1.0

Hf Hf Hf Hf Mg Mg Mg Mg
Hf Hf Hf Hf Mg Mg Mg Mg 0 5 o o o 0 4 o o + 1 5 o + o 1 3 + + o 1 3 o + o 1 4 o o o 1 6 + o o 1 6 o o o 2 7 o o o 2 3 o + + 3 5 - o o 3 4 - o o 3 4 o o o 3 7 o - o 3 6 o - o 3 6 o o o 4 6 o o o 4 6 + o o 6 7 o o o 
Mg(Hf) crystallizes in the triclinic P1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 1-coordinate geometry to one Hf(1) and two equivalent Hf(4) atoms. The Mg(1)-Hf(1) bond length is 2.29 Å. There is one shorter (2.93 Å) and one longer (2.95 Å) Mg(1)-Hf(4) bond length. In the second Mg site, Mg(2) is bonded in a distorted linear geometry to one Hf(1) and one Hf(2) atom. The Mg(2)-Hf(1) bond length is 1.13 Å. The Mg(2)-Hf(2) bond length is 1.83 Å. In the third Mg site, Mg(3) is bonded in a 1-coordinate geometry to one Mg(4) and one Hf(4) atom. The Mg(3)-Mg(4) bond length is 2.30 Å. The Mg(3)-Hf(4) bond length is 3.10 Å. In the fourth Mg site, Mg(4) is bonded in a 1-coordinate geometry to one Mg(3), one Hf(3), and one Hf(4) atom. The Mg(4)-Hf(3) bond length is 1.76 Å. The Mg(4)-Hf(4) bond length is 2.98 Å. There are four inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a distorted linear geometry to one Mg(1) and one Mg(2) atom. In the second Hf site, Hf(2) is bonded in a distorted single-bond geometry to one Mg(2) atom. In the third Hf site, Hf(3) is bonded in a distorted single-bond geometry to one Mg(4) and one Hf(4) atom. The Hf(3)-Hf(4) bond length is 2.69 Å. In the fourth Hf site, Hf(4) is bonded in a 5-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(1), and one Hf(3) atom.