data_NbAlSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.94
_cell_length_b   7.94
_cell_length_c   7.94
_cell_angle_alpha   22.61
_cell_angle_beta   22.61
_cell_angle_gamma   22.61
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NbAlSi2
_chemical_formula_sum   'Nb1 Al1 Si2'
_cell_volume   65.02
_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  0.0  0.0  0.61  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  Si  Si2  1  0.0  0.0  0.41  1.0
  Si  Si3  1  0.0  0.0  0.81  1.0

data_NbAlSi2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.39
_cell_length_b   3.11
_cell_length_c   7.94
_cell_angle_alpha   90.0
_cell_angle_beta   103.08
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   NbAlSi2
_chemical_formula_sum   'Nb2 Al2 Si4'
_cell_volume   130.03
_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
  Nb  Nb0  2  -0.0  0.0  0.39  1.0
  Al  Al1  2  0.0  0.0  0.0  1.0
  Si  Si2  2  -0.0  0.0  0.59  1.0
  Si  Si3  2  -0.0  0.0  0.19  1.0

Nb Al Si Si
Nb Al Si Si 0 2 o o o 0 3 o o o 1 3 o o - 
NbAlSi2 is Cyanogen Chloride-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two NbAlSi2 clusters. Nb(1) is bonded in a linear geometry to one Si(1) and one Si(2) atom. The Nb(1)-Si(1) bond length is 1.59 Å. The Nb(1)-Si(2) bond length is 1.59 Å. Al(1) is bonded in a single-bond geometry to one Si(2) atom. The Al(1)-Si(2) bond length is 1.53 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a single-bond geometry to one Nb(1) atom. In the second Si site, Si(2) is bonded in a linear geometry to one Nb(1) and one Al(1) atom.