data_AlCuNi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.63
_cell_length_b   2.63
_cell_length_c   6.85
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   92.27
_symmetry_Int_Tables_number   1
_chemical_formula_structural   AlCuNi2
_chemical_formula_sum   'Al1 Cu1 Ni2'
_cell_volume   47.52
_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
  Al  Al0  1  0.0  0.0  0.52  1.0
  Cu  Cu1  1  0.83  0.0  0.67  1.0
  Ni  Ni2  1  0.0  0.0  0.8  1.0
  Ni  Ni3  1  0.83  0.0  0.13  1.0

data_AlCuNi2
_symmetry_space_group_name_H-M   Pm
_cell_length_a   2.63
_cell_length_b   2.63
_cell_length_c   6.85
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   AlCuNi2
_chemical_formula_sum   'Al1 Cu1 Ni2'
_cell_volume   47.56
_cell_formula_units_Z   1
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
  Al  Al0  1  0.0  0.0  0.52  1.0
  Cu  Cu1  1  0.83  0.0  0.67  1.0
  Ni  Ni2  1  0.0  0.0  0.8  1.0
  Ni  Ni3  1  0.83  0.0  0.13  1.0

Al Cu Ni Ni
Ni2CuAl crystallizes in the monoclinic Pm space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a single-bond geometry to one Ni(2) and one Cu(1) atom. The Ni(1)-Ni(2) bond length is 2.31 Å. The Ni(1)-Cu(1) bond length is 0.98 Å. In the second Ni site, Ni(2) is bonded to one Ni(1), four equivalent Ni(2), and one Al(1) atom to form a mixture of distorted corner and edge-sharing NiAlNi5 octahedra. The corner-sharing octahedra are not tilted. All Ni(2)-Ni(2) bond lengths are 2.63 Å. The Ni(2)-Al(1) bond length is 2.73 Å. Cu(1) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and one Al(1) atom. The Cu(1)-Al(1) bond length is 1.13 Å. Al(1) is bonded in a single-bond geometry to one Ni(2) and one Cu(1) atom.