data_Na2BeSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.13
_cell_length_b   3.13
_cell_length_c   8.4
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2BeSi
_chemical_formula_sum   'Na2 Be1 Si1'
_cell_volume   82.55
_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  Na1  1  0.57  0.57  0.9  1.0
  Na  Na2  1  0.0  0.0  0.59  1.0
  Be  Be0  1  0.0  0.0  0.69  1.0
  Si  Si3  1  0.57  0.57  0.83  1.0

data_Na2BeSi
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.43
_cell_length_b   4.43
_cell_length_c   8.4
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na2BeSi
_chemical_formula_sum   'Na4 Be2 Si2'
_cell_volume   165.1
_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  0.59  1.0
  Na  Na1  2  0.07  0.5  0.9  1.0
  Be  Be2  2  0.0  0.0  0.69  1.0
  Si  Si3  2  0.07  0.5  0.83  1.0

Na Na Be Si
NaBeNaSi is beta oxygen-derived structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two sodium silanide molecules and two NaBe clusters. In each NaBe cluster, Na(2) is bonded in a single-bond geometry to one Be(1) atom. The Na(2)-Be(1) bond length is 0.89 Å. Be(1) is bonded in a single-bond geometry to one Na(2) atom.