data_CaYSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.22
_cell_length_b   5.22
_cell_length_c   5.22
_cell_angle_alpha   127.07
_cell_angle_beta   127.07
_cell_angle_gamma   78.14
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaYSi2
_chemical_formula_sum   'Ca1 Y1 Si2'
_cell_volume   87.72
_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
  Ca  Ca0  1  0.0  0.0  0.0  1.0
  Y  Y3  1  0.0  0.0  0.05  1.0
  Si  Si1  1  0.0  0.33  0.03  1.0
  Si  Si2  1  0.33  0.0  0.03  1.0

data_CaYSi2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.58
_cell_length_b   6.58
_cell_length_c   5.22
_cell_angle_alpha   90.0
_cell_angle_beta   129.07
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   CaYSi2
_chemical_formula_sum   'Ca2 Y2 Si4'
_cell_volume   175.43
_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
  Ca  Ca0  2  0.0  0.0  0.0  1.0
  Y  Y1  2  0.0  0.0  0.05  1.0
  Si  Si2  4  0.34  0.34  0.7  1.0

Ca Y Si Si
Ca Y Si Si 0 1 o o o 0 2 o o o 0 3 o o o 1 2 o o o 1 3 o o o 
CaYSi2 is Copper structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two CaYSi2 clusters. Ca(1) is bonded in a distorted single-bond geometry to one Y(1) and two equivalent Si(1) atoms. The Ca(1)-Y(1) bond length is 0.27 Å. Both Ca(1)-Si(1) bond lengths are 1.62 Å. Y(1) is bonded in a single-bond geometry to one Ca(1) atom. Si(1) is bonded in a single-bond geometry to one Ca(1) atom.