data_Na2ReSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.74
_cell_length_b   5.74
_cell_length_c   5.74
_cell_angle_alpha   141.59
_cell_angle_beta   141.59
_cell_angle_gamma   55.44
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2ReSe
_chemical_formula_sum   'Na2 Re1 Se1'
_cell_volume   72.61
_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  0.89  0.0  0.54  1.0
  Na  Na1  1  0.0  0.89  0.54  1.0
  Re  Re2  1  0.0  0.0  0.09  1.0
  Se  Se3  1  0.0  0.0  0.0  1.0

data_Na2ReSe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.34
_cell_length_b   5.34
_cell_length_c   5.74
_cell_angle_alpha   90.0
_cell_angle_beta   117.72
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na2ReSe
_chemical_formula_sum   'Na4 Re2 Se2'
_cell_volume   145.23
_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  4  0.44  0.44  0.35  1.0
  Re  Re1  2  0.0  0.0  0.91  1.0
  Se  Se2  2  0.0  0.0  0.0  1.0

Na Na Re Se
Na Na Re Se 0 1 + - o 2 3 o o o 
Na2ReSe crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Na2ReSe clusters. Na(1) is bonded in a 2-coordinate geometry to one Na(1) and one Se(1) atom. The Na(1)-Na(1) bond length is 0.59 Å. The Na(1)-Se(1) bond length is 2.17 Å. Re(1) is bonded in a single-bond geometry to one Se(1) atom. The Re(1)-Se(1) bond length is 0.49 Å. Se(1) is bonded in a distorted single-bond geometry to two equivalent Na(1) and one Re(1) atom.