data_SrTlSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.65
_cell_length_b   4.65
_cell_length_c   4.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrTlSi2
_chemical_formula_sum   'Sr1 Tl1 Si2'
_cell_volume   95.25
_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
  Sr  Sr2  1  0.0  0.0  0.0  1.0
  Tl  Tl3  1  0.32  0.32  0.0  1.0
  Si  Si0  1  0.32  0.0  0.21  1.0
  Si  Si1  1  0.0  0.32  0.21  1.0

data_SrTlSi2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.57
_cell_length_b   6.57
_cell_length_c   4.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   SrTlSi2
_chemical_formula_sum   'Sr2 Tl2 Si4'
_cell_volume   190.49
_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
  Sr  Sr0  2  0.0  0.0  0.0  1.0
  Tl  Tl1  2  0.32  0.0  -0.0  1.0
  Si  Si2  4  0.16  0.16  0.21  1.0

Sr Tl Si Si
SrTlSi2 is alpha Po structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two SrTlSi2 clusters. Sr(1) is bonded in a 2-coordinate geometry to one Tl(1) and two equivalent Si(1) atoms. The Sr(1)-Tl(1) bond length is 2.12 Å. Both Sr(1)-Si(1) bond lengths are 1.76 Å. Tl(1) is bonded in a 3-coordinate geometry to one Sr(1) and two equivalent Si(1) atoms. Both Tl(1)-Si(1) bond lengths are 1.76 Å. Si(1) is bonded in a 2-coordinate geometry to one Sr(1) and one Tl(1) atom.