data_Ba2YSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.63
_cell_length_b   6.63
_cell_length_c   6.63
_cell_angle_alpha   137.74
_cell_angle_beta   135.8
_cell_angle_gamma   62.81
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2YSi
_chemical_formula_sum   'Ba2 Y1 Si1'
_cell_volume   135.11
_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  0.39  0.0  0.68  1.0
  Ba  Ba1  1  0.0  0.5  0.98  1.0
  Y  Y3  1  0.0  0.0  0.66  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0

data_Ba2YSi
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.78
_cell_length_b   4.99
_cell_length_c   6.63
_cell_angle_alpha   112.1
_cell_angle_beta   111.13
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2YSi
_chemical_formula_sum   'Ba2 Y1 Si1'
_cell_volume   135.11
_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  0.0  0.68  0.29  1.0
  Ba  Ba1  1  0.5  0.48  0.48  1.0
  Y  Y2  1  0.0  0.66  0.66  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0

Ba Ba Y Si
Ba2YSi crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 3-coordinate geometry to one Y(1) and two equivalent Si(1) atoms. The Ba(1)-Y(1) bond length is 2.49 Å. There is one shorter (2.92 Å) and one longer (3.22 Å) Ba(1)-Si(1) bond length. In the second Ba site, Ba(2) is bonded in a 1-coordinate geometry to two equivalent Y(1) and one Si(1) atom. There is one shorter (2.23 Å) and one longer (3.04 Å) Ba(2)-Y(1) bond length. The Ba(2)-Si(1) bond length is 3.24 Å. Y(1) is bonded in a 4-coordinate geometry to one Ba(1), two equivalent Ba(2), and one Si(1) atom. The Y(1)-Si(1) bond length is 2.25 Å. Si(1) is bonded in a 4-coordinate geometry to one Ba(2), two equivalent Ba(1), and one Y(1) atom.