data_Sc2TaSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.96
_cell_length_b   2.96
_cell_length_c   8.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sc2TaSi
_chemical_formula_sum   'Sc2 Ta1 Si1'
_cell_volume   75.72
_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
  Sc  Sc0  1  0.48  0.48  0.66  1.0
  Sc  Sc1  1  0.48  0.48  0.99  1.0
  Ta  Ta3  1  0.0  0.0  0.33  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0

data_Sc2TaSi
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.18
_cell_length_b   4.18
_cell_length_c   8.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Sc2TaSi
_chemical_formula_sum   'Sc4 Ta2 Si2'
_cell_volume   151.44
_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
  Sc  Sc0  2  0.48  0.0  0.66  1.0
  Sc  Sc1  2  0.48  0.0  0.99  1.0
  Ta  Ta2  2  0.0  0.0  0.33  1.0
  Si  Si3  2  0.0  0.0  0.0  1.0

Sc Sc Ta Si
Sc Sc Ta Si 0 2 o o o 0 2 o + o 0 2 + o o 0 3 o o + 0 3 o + + 0 3 + o + 0 0 + o o 0 0 o + o 0 1 o o o 1 3 o o + 1 3 o + + 1 3 + o + 1 3 + + + 1 2 + o + 1 2 o + + 1 2 o o + 2 2 + o o 2 2 o + o 2 3 o o o 
Sc2TaSi crystallizes in the monoclinic Cm space group. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 9-coordinate geometry to one Sc(2), four equivalent Sc(1), and four equivalent Ta(1) atoms. The Sc(1)-Sc(2) bond length is 2.86 Å. All Sc(1)-Sc(1) bond lengths are 2.96 Å. There are a spread of Sc(1)-Ta(1) bond distances ranging from 3.52-3.63 Å. In the second Sc site, Sc(2) is bonded in a square co-planar geometry to one Sc(1) and four equivalent Si(1) atoms. There are a spread of Sc(2)-Si(1) bond distances ranging from 2.00-2.18 Å. Ta(1) is bonded in a distorted single-bond geometry to four equivalent Sc(1) and one Si(1) atom. The Ta(1)-Si(1) bond length is 2.85 Å. Si(1) is bonded to four equivalent Sc(2) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing SiSc4Ta square pyramids.