data_HfNbAl4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.21
_cell_length_b   5.21
_cell_length_c   5.21
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfNbAl4
_chemical_formula_sum   'Hf1 Nb1 Al4'
_cell_volume   99.82
_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  Hf4  1  0.84  0.84  0.84  1.0
  Nb  Nb5  1  0.0  0.0  0.0  1.0
  Al  Al0  1  0.76  0.6  0.76  1.0
  Al  Al1  1  0.6  0.76  0.76  1.0
  Al  Al2  1  0.6  0.6  0.6  1.0
  Al  Al3  1  0.76  0.76  0.6  1.0

data_HfNbAl4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.21
_cell_length_b   5.21
_cell_length_c   12.75
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   HfNbAl4
_chemical_formula_sum   'Hf3 Nb3 Al12'
_cell_volume   299.47
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.16  1.0
  Nb  Nb1  3  0.0  0.0  0.0  1.0
  Al  Al2  9  0.11  0.05  0.29  1.0
  Al  Al3  3  0.0  0.0  0.4  1.0

Hf Nb Al Al Al Al
HfNbAl4 crystallizes in the trigonal R3m space group. Hf(1) is bonded in a 4-coordinate geometry to one Nb(1), three equivalent Al(1), and three equivalent Al(2) atoms. The Hf(1)-Nb(1) bond length is 2.03 Å. All Hf(1)-Al(1) bond lengths are 1.75 Å. All Hf(1)-Al(2) bond lengths are 3.23 Å. Nb(1) is bonded in a distorted single-bond geometry to one Hf(1) and three equivalent Al(1) atoms. All Nb(1)-Al(1) bond lengths are 2.57 Å. There are two inequivalent Al sites. In the first Al site, Al(2) is bonded in a 6-coordinate geometry to three equivalent Hf(1) and three equivalent Al(1) atoms. All Al(2)-Al(1) bond lengths are 1.47 Å. In the second Al site, Al(1) is bonded in a 5-coordinate geometry to one Hf(1), one Nb(1), one Al(2), and two equivalent Al(1) atoms. Both Al(1)-Al(1) bond lengths are 0.85 Å.