data_Ta2SiSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.15
_cell_length_b   5.15
_cell_length_c   5.15
_cell_angle_alpha   134.91
_cell_angle_beta   134.91
_cell_angle_gamma   65.67
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2SiSe
_chemical_formula_sum   'Ta2 Si1 Se1'
_cell_volume   67.65
_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
  Ta  Ta2  1  0.98  0.0  0.17  1.0
  Ta  Ta3  1  0.0  0.0  0.33  1.0
  Si  Si1  1  0.0  0.0  0.0  1.0
  Se  Se0  1  0.0  0.98  0.17  1.0

data_Ta2SiSe
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.95
_cell_length_b   3.95
_cell_length_c   5.15
_cell_angle_alpha   112.55
_cell_angle_beta   112.55
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2SiSe
_chemical_formula_sum   'Ta2 Si1 Se1'
_cell_volume   67.65
_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
  Ta  Ta0  1  0.67  0.0  0.67  1.0
  Ta  Ta1  1  0.83  0.0  0.81  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.81  0.98  0.81  1.0

Ta Ta Si Se
Ta2SiSe crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one Ta2SiSe cluster. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a single-bond geometry to one Si(1) and one Se(1) atom. The Ta(1)-Si(1) bond length is 0.94 Å. The Ta(1)-Se(1) bond length is 0.13 Å. In the second Ta site, Ta(2) is bonded in a distorted single-bond geometry to one Se(1) atom. The Ta(2)-Se(1) bond length is 0.77 Å. Si(1) is bonded in a 2-coordinate geometry to one Ta(1) and one Se(1) atom. The Si(1)-Se(1) bond length is 0.94 Å. Se(1) is bonded in a single-bond geometry to one Ta(1), one Ta(2), and one Si(1) atom.