data_HfAl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.17
_cell_length_b   5.17
_cell_length_c   5.17
_cell_angle_alpha   34.38
_cell_angle_beta   34.38
_cell_angle_gamma   34.38
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfAl
_chemical_formula_sum   'Hf1 Al1'
_cell_volume   39.4
_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  Hf1  1  0.0  0.0  0.3  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0

data_HfAl
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.3
_cell_length_b   3.06
_cell_length_c   5.17
_cell_angle_alpha   90.0
_cell_angle_beta   109.95
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   HfAl
_chemical_formula_sum   'Hf2 Al2'
_cell_volume   78.8
_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  0.7  1.0
  Al  Al1  2  0.0  0.0  0.0  1.0

Hf Al
Hf Al 0 1 o o o 
HfAl is alpha carbon monoxide-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two HfAl clusters. Hf(1) is bonded in a single-bond geometry to one Al(1) atom. The Hf(1)-Al(1) bond length is 1.53 Å. Al(1) is bonded in a single-bond geometry to one Hf(1) atom.