data_Ba2CaSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.62
_cell_length_b   7.67
_cell_length_c   7.67
_cell_angle_alpha   40.27
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2CaSi
_chemical_formula_sum   'Ba2 Ca1 Si1'
_cell_volume   175.74
_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  0.31  0.0  0.64  1.0
  Ba  Ba1  1  0.0  0.0  0.25  1.0
  Ca  Ca2  1  0.31  0.0  0.38  1.0
  Si  Si3  1  0.0  0.0  0.55  1.0

data_Ba2CaSi
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.62
_cell_length_b   5.28
_cell_length_c   7.67
_cell_angle_alpha   110.14
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2CaSi
_chemical_formula_sum   'Ba2 Ca1 Si1'
_cell_volume   175.74
_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  0.25  0.25  1.0
  Ba  Ba1  1  0.69  0.64  0.64  1.0
  Ca  Ca2  1  0.69  0.38  0.38  1.0
  Si  Si3  1  0.0  0.55  0.55  1.0

Ba Ba Ca Si
Ba2CaSi crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one Ba2CaSi cluster. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a distorted single-bond geometry to one Ca(1) and one Si(1) atom. The Ba(1)-Ca(1) bond length is 1.96 Å. The Ba(1)-Si(1) bond length is 1.60 Å. In the second Ba site, Ba(2) is bonded in a 2-coordinate geometry to one Ca(1) and one Si(1) atom. The Ba(2)-Ca(1) bond length is 1.74 Å. The Ba(2)-Si(1) bond length is 2.24 Å. Ca(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), and one Si(1) atom. The Ca(1)-Si(1) bond length is 1.90 Å. Si(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), and one Ca(1) atom.