data_YAlSn
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.98
_cell_length_b   4.98
_cell_length_c   4.98
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YAlSn
_chemical_formula_sum   'Y1 Al1 Sn1'
_cell_volume   87.51
_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  0.76  0.76  0.76  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  Sn  Sn1  1  0.52  0.52  0.52  1.0

data_YAlSn
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.98
_cell_length_b   4.98
_cell_length_c   12.21
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   YAlSn
_chemical_formula_sum   'Y3 Al3 Sn3'
_cell_volume   262.53
_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  0.24  1.0
  Al  Al1  3  0.0  0.0  1.0  1.0
  Sn  Sn2  3  0.0  0.0  0.48  1.0

Y Al Sn
YAlSn is half-Heusler structured and crystallizes in the trigonal R3m space group. Y(1) is bonded in a body-centered cubic geometry to four equivalent Al(1) and four equivalent Sn(1) atoms. There is one shorter (2.91 Å) and three longer (3.10 Å) Y(1)-Al(1) bond lengths. There is one shorter (2.91 Å) and three longer (3.10 Å) Y(1)-Sn(1) bond lengths. Al(1) is bonded to four equivalent Y(1) atoms to form AlY4 tetrahedra that share corners with four equivalent Sn(1)Y4 tetrahedra, corners with twelve equivalent Al(1)Y4 tetrahedra, and edges with six equivalent Sn(1)Y4 tetrahedra. Sn(1) is bonded to four equivalent Y(1) atoms to form SnY4 tetrahedra that share corners with four equivalent Al(1)Y4 tetrahedra, corners with twelve equivalent Sn(1)Y4 tetrahedra, and edges with six equivalent Al(1)Y4 tetrahedra.