data_LaSi2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.18
_cell_length_b   4.18
_cell_length_c   4.93
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   LaSi2Se
_chemical_formula_sum   'La1 Si2 Se1'
_cell_volume   85.96
_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
  La  La0  1  0.09  0.09  0.0  1.0
  Si  Si2  1  0.0  0.09  0.47  1.0
  Si  Si3  1  0.09  0.0  0.47  1.0
  Se  Se1  1  0.0  0.0  0.0  1.0

data_LaSi2Se
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.9
_cell_length_b   5.9
_cell_length_c   4.93
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   LaSi2Se
_chemical_formula_sum   'La2 Si4 Se2'
_cell_volume   171.92
_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
  La  La0  2  0.09  0.0  0.0  1.0
  Si  Si1  4  0.04  0.04  0.47  1.0
  Se  Se2  2  0.0  0.0  0.0  1.0

La Si Si Se
La Si Si Se 0 3 o o o 1 2 o o o 
LaSe(Si)2 crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two disilane molecules and two LaSe clusters. In each LaSe cluster, La(1) is bonded in a single-bond geometry to one Se(1) atom. The La(1)-Se(1) bond length is 0.52 Å. Se(1) is bonded in a single-bond geometry to one La(1) atom.