data_NbAlNi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.08
_cell_length_b   4.08
_cell_length_c   4.08
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NbAlNi
_chemical_formula_sum   'Nb1 Al1 Ni1'
_cell_volume   48.05
_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
  Nb  Nb1  1  0.89  0.89  0.89  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  Ni  Ni2  1  0.44  0.44  0.44  1.0

data_NbAlNi
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.08
_cell_length_b   4.08
_cell_length_c   10.0
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NbAlNi
_chemical_formula_sum   'Nb3 Al3 Ni3'
_cell_volume   144.16
_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
  Nb  Nb0  3  0.0  0.0  0.11  1.0
  Al  Al1  3  0.0  0.0  -0.0  1.0
  Ni  Ni2  3  0.0  0.0  0.56  1.0

Nb Al Ni
Nb Al Ni 0 1 + + + 0 2 + o o 0 2 o + o 0 2 o o + 1 2 o o - 1 2 o - o 1 2 - o o 
NiAlNb crystallizes in the trigonal R3m space group. Nb(1) is bonded to three equivalent Ni(1) and one Al(1) atom to form distorted NbAlNi3 tetrahedra that share corners with three equivalent Ni(1)Nb3Al3 octahedra, corners with three equivalent Al(1)NbNi3 tetrahedra, corners with six equivalent Nb(1)AlNi3 tetrahedra, and edges with three equivalent Al(1)NbNi3 tetrahedra. The corner-sharing octahedral tilt angles are 65°. All Nb(1)-Ni(1) bond lengths are 2.60 Å. The Nb(1)-Al(1) bond length is 1.14 Å. Ni(1) is bonded to three equivalent Nb(1) and three equivalent Al(1) atoms to form distorted NiNb3Al3 octahedra that share corners with three equivalent Nb(1)AlNi3 tetrahedra, corners with three equivalent Al(1)NbNi3 tetrahedra, and edges with six equivalent Ni(1)Nb3Al3 octahedra. All Ni(1)-Al(1) bond lengths are 2.60 Å. Al(1) is bonded to one Nb(1) and three equivalent Ni(1) atoms to form distorted AlNbNi3 tetrahedra that share corners with three equivalent Ni(1)Nb3Al3 octahedra, corners with three equivalent Nb(1)AlNi3 tetrahedra, corners with six equivalent Al(1)NbNi3 tetrahedra, and edges with three equivalent Nb(1)AlNi3 tetrahedra. The corner-sharing octahedral tilt angles are 65°.