data_NaSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.83
_cell_length_b   4.83
_cell_length_c   3.82
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   104.43
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaSe3
_chemical_formula_sum   'Na1 Se3'
_cell_volume   86.08
_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  Na0  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.48  0.91  0.91  1.0
  Se  Se2  1  0.48  0.09  0.91  1.0
  Se  Se3  1  0.96  0.0  0.0  1.0

data_NaSe3
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.82
_cell_length_b   4.83
_cell_length_c   4.83
_cell_angle_alpha   104.43
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaSe3
_chemical_formula_sum   'Na1 Se3'
_cell_volume   86.08
_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  Na0  1  0.0  0.0  0.0  1.0
  Se  Se1  1  -0.0  0.96  0.0  1.0
  Se  Se2  1  0.91  0.48  0.09  1.0
  Se  Se3  1  0.91  0.48  0.91  1.0

Na Se Se Se
Na Se Se Se 0 3 - o o 1 2 o + o 
NaSe3 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one NaSe3 cluster. Na(1) is bonded in a single-bond geometry to one Se(2) and one Se(3) atom. The Na(1)-Se(2) bond length is 2.26 Å. The Na(1)-Se(3) bond length is 0.21 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted single-bond geometry to one Se(2) atom. The Se(1)-Se(2) bond length is 0.90 Å. In the second Se site, Se(2) is bonded in an L-shaped geometry to one Na(1) and one Se(1) atom. In the third Se site, Se(3) is bonded in a single-bond geometry to one Na(1) atom.