data_YSiCl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.81
_cell_length_b   4.81
_cell_length_c   4.81
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YSiCl
_chemical_formula_sum   'Y1 Si1 Cl1'
_cell_volume   78.6
_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
  Y  Y2  1  0.7  0.7  0.7  1.0
  Si  Si1  1  0.0  0.0  0.0  1.0
  Cl  Cl0  1  0.4  0.4  0.4  1.0

data_YSiCl
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.81
_cell_length_b   4.81
_cell_length_c   11.78
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   YSiCl
_chemical_formula_sum   'Y3 Si3 Cl3'
_cell_volume   235.81
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Y  Y0  3  0.0  0.0  0.3  1.0
  Si  Si1  3  0.0  0.0  0.0  1.0
  Cl  Cl2  3  0.0  0.0  0.6  1.0

Y Si Cl
YSiCl is half-Heusler structured and crystallizes in the trigonal R3m space group. Y(1) is bonded to four equivalent Si(1) and four equivalent Cl(1) atoms to form distorted YSi4Cl4 hexagonal bipyramids that share corners with six equivalent Si(1)Y4Cl3 hexagonal pyramids, edges with twelve equivalent Y(1)Si4Cl4 hexagonal bipyramids, and edges with three equivalent Si(1)Y4Cl3 hexagonal pyramids. There are three shorter (2.80 Å) and one longer (3.53 Å) Y(1)-Si(1) bond length. There are three shorter (2.80 Å) and one longer (3.53 Å) Y(1)-Cl(1) bond length. Si(1) is bonded to four equivalent Y(1) and three equivalent Cl(1) atoms to form distorted SiY4Cl3 hexagonal pyramids that share corners with six equivalent Y(1)Si4Cl4 hexagonal bipyramids, corners with six equivalent Si(1)Y4Cl3 hexagonal pyramids, edges with three equivalent Y(1)Si4Cl4 hexagonal bipyramids, and edges with six equivalent Si(1)Y4Cl3 hexagonal pyramids. All Si(1)-Cl(1) bond lengths are 2.88 Å. Cl(1) is bonded in a 7-coordinate geometry to four equivalent Y(1) and three equivalent Si(1) atoms.