data_NaCr2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.74
_cell_length_b   4.74
_cell_length_c   4.74
_cell_angle_alpha   133.8
_cell_angle_beta   133.8
_cell_angle_gamma   67.4
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaCr2Si
_chemical_formula_sum   'Na1 Cr2 Si1'
_cell_volume   54.45
_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
  Na  Na2  1  0.0  0.0  0.0  1.0
  Cr  Cr0  1  0.0  0.86  0.97  1.0
  Cr  Cr1  1  0.86  0.0  0.97  1.0
  Si  Si3  1  0.0  0.0  0.94  1.0

data_NaCr2Si
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.26
_cell_length_b   5.26
_cell_length_c   4.74
_cell_angle_alpha   90.0
_cell_angle_beta   123.7
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   NaCr2Si
_chemical_formula_sum   'Na2 Cr4 Si2'
_cell_volume   108.91
_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
  Na  Na0  2  0.0  0.0  0.0  1.0
  Cr  Cr1  4  0.46  0.43  0.89  1.0
  Si  Si2  2  0.06  0.0  0.06  1.0

Na Cr Cr Si
Na Cr Cr Si 0 3 o o - 0 1 o - - 0 2 - o - 
NaCr2Si crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two NaCr2Si clusters. Na(1) is bonded in a 3-coordinate geometry to two equivalent Cr(1) and one Si(1) atom. Both Na(1)-Cr(1) bond lengths are 0.58 Å. The Na(1)-Si(1) bond length is 0.28 Å. Cr(1) is bonded in a single-bond geometry to one Na(1) atom. Si(1) is bonded in a single-bond geometry to one Na(1) atom.