data_Al4Si2Ni
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.59
_cell_length_b   2.77
_cell_length_c   10.5
_cell_angle_alpha   90.0
_cell_angle_beta   105.76
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Al4Si2Ni
_chemical_formula_sum   'Al8 Si4 Ni2'
_cell_volume   212.36
_cell_formula_units_Z   2
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  0.75  0.08  0.56  1.0
  Al  Al1  1  0.99  0.69  0.54  1.0
  Al  Al2  1  0.26  0.08  0.8  1.0
  Al  Al3  1  0.48  0.69  0.31  1.0
  Al  Al4  1  0.63  0.08  0.35  1.0
  Al  Al5  1  0.11  0.69  0.75  1.0
  Al  Al6  1  0.63  0.08  0.79  1.0
  Al  Al7  1  0.11  0.69  0.32  1.0
  Si  Si10  1  0.75  0.08  0.8  1.0
  Si  Si11  1  1.0  0.69  0.3  1.0
  Si  Si12  1  0.01  0.08  0.04  1.0
  Si  Si13  1  0.73  0.69  0.07  1.0
  Ni  Ni8  1  0.35  0.69  0.02  1.0
  Ni  Ni9  1  0.39  0.08  0.08  1.0

data_Al4Si2Ni
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.77
_cell_length_b   7.59
_cell_length_c   10.5
_cell_angle_alpha   105.76
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Al4Si2Ni
_chemical_formula_sum   'Al8 Si4 Ni2'
_cell_volume   212.36
_cell_formula_units_Z   2
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  2  0.19  0.39  0.24  1.0
  Al  Al1  2  0.19  0.76  0.8  1.0
  Al  Al2  2  0.19  0.76  0.23  1.0
  Al  Al3  2  0.19  0.88  0.01  1.0
  Si  Si4  2  0.19  0.14  0.48  1.0
  Si  Si5  2  0.19  0.88  0.25  1.0
  Ni  Ni6  2  0.19  0.52  0.53  1.0

Al Al Al Al Al Al Al Al Si Si Si Si Ni Ni
NiAl4Si2 crystallizes in the triclinic P-1 space group. Ni(1) is bonded in a 1-coordinate geometry to one Ni(1), one Al(2), and two equivalent Si(2) atoms. The Ni(1)-Ni(1) bond length is 1.22 Å. The Ni(1)-Al(2) bond length is 2.54 Å. There is one shorter (2.78 Å) and one longer (2.79 Å) Ni(1)-Si(2) bond length. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a 3-coordinate geometry to one Al(1), one Al(3), and one Si(1) atom. The Al(1)-Al(1) bond length is 2.17 Å. The Al(1)-Al(3) bond length is 2.12 Å. The Al(1)-Si(1) bond length is 2.55 Å. In the second Al site, Al(2) is bonded in a 3-coordinate geometry to one Ni(1) and two equivalent Al(3) atoms. There is one shorter (1.54 Å) and one longer (2.04 Å) Al(2)-Al(3) bond length. In the third Al site, Al(3) is bonded in a distorted trigonal non-coplanar geometry to one Al(1) and two equivalent Al(2) atoms. In the fourth Al site, Al(4) is bonded in a single-bond geometry to one Si(1) and one Si(2) atom. The Al(4)-Si(1) bond length is 0.83 Å. The Al(4)-Si(2) bond length is 3.04 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a single-bond geometry to one Al(1), one Al(4), and one Si(2) atom. The Si(1)-Si(2) bond length is 2.73 Å. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to two equivalent Ni(1), one Al(4), one Si(1), and four equivalent Si(2) atoms. There are a spread of Si(2)-Si(2) bond distances ranging from 2.53-2.86 Å.