data_BaTiSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.24
_cell_length_b   5.24
_cell_length_c   3.67
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaTiSe2
_chemical_formula_sum   'Ba1 Ti1 Se2'
_cell_volume   100.57
_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
  Ba  Ba0  1  0.62  0.62  0.0  1.0
  Ti  Ti3  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.62  0.0  0.83  1.0
  Se  Se2  1  0.0  0.62  0.83  1.0

data_BaTiSe2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   7.4
_cell_length_b   7.4
_cell_length_c   3.67
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BaTiSe2
_chemical_formula_sum   'Ba2 Ti2 Se4'
_cell_volume   201.13
_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
  Ba  Ba0  2  0.12  0.5  -0.0  1.0
  Ti  Ti1  2  0.0  0.0  0.0  1.0
  Se  Se2  4  0.31  0.31  0.83  1.0

Ba Ti Se Se
BaTiSe2 crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two BaTiSe2 clusters. Ba(1) is bonded in a distorted L-shaped geometry to two equivalent Se(1) atoms. Both Ba(1)-Se(1) bond lengths are 2.09 Å. Ti(1) is bonded in a distorted L-shaped geometry to two equivalent Se(1) atoms. Both Ti(1)-Se(1) bond lengths are 2.09 Å. Se(1) is bonded in a distorted L-shaped geometry to one Ba(1) and one Ti(1) atom.