data_Hf2MgSb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.78
_cell_length_b   3.78
_cell_length_c   6.22
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Hf2MgSb
_chemical_formula_sum   'Hf2 Mg1 Sb1'
_cell_volume   89.02
_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
  Hf  Hf0  1  0.0  0.0  0.03  1.0
  Hf  Hf1  1  0.89  0.89  0.49  1.0
  Mg  Mg2  1  0.0  0.0  0.11  1.0
  Sb  Sb3  1  0.89  0.89  0.7  1.0

data_Hf2MgSb
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.35
_cell_length_b   5.35
_cell_length_c   6.22
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Hf2MgSb
_chemical_formula_sum   'Hf4 Mg2 Sb2'
_cell_volume   178.04
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.03  1.0
  Hf  Hf1  2  0.39  0.5  0.49  1.0
  Mg  Mg2  2  0.0  0.0  0.11  1.0
  Sb  Sb3  2  0.39  0.5  0.7  1.0

Hf Hf Mg Sb
Hf Hf Mg Sb 0 2 o o o 1 3 o o o 
MgHf2Sb crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two MgHf2Sb clusters. Mg(1) is bonded in a distorted single-bond geometry to one Hf(1) atom. The Mg(1)-Hf(1) bond length is 0.52 Å. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a linear geometry to one Mg(1) and one Sb(1) atom. The Hf(1)-Sb(1) bond length is 2.16 Å. In the second Hf site, Hf(2) is bonded in a single-bond geometry to one Sb(1) atom. The Hf(2)-Sb(1) bond length is 1.28 Å. Sb(1) is bonded in a distorted linear geometry to one Hf(1) and one Hf(2) atom.