The material described by YSi crystallizes in the hexagonal P-62m space group. Y(1) is bonded to one Si(1) and four equivalent Si(2) atoms to form a mixture of edge and corner-sharing YSi5 square pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a trigonal planar geometry to three equivalent Y(1) atoms. In the second Si site, Si(2) is bonded to six equivalent Y(1) atoms to form a mixture of distorted edge, corner, and face-sharing SiY6 pentagonal pyramids. is represented by the CIF file [CIF]
data_YSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.961
_cell_length_b   6.961
_cell_length_c   4.088
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   171.547
_cell_formula_units_Z   3
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  Y0  1  0.000  0.431  0.000  1.0
  Y  Y1  1  0.569  0.569  0.000  1.0
  Y  Y2  1  0.431  0.000  0.000  1.0
  Si  Si3  1  0.000  0.000  0.000  1.0
  Si  Si4  1  0.333  0.667  0.500  1.0
  Si  Si5  1  0.667  0.333  0.500  1.0
[/CIF]
.
The material described by YSi crystallizes in the hexagonal P-62m space group. Y(1) is bonded to one Si(1) and four equivalent Si(2) atoms to form a mixture of edge and corner-sharing YSi5 square pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a trigonal planar geometry to three equivalent Y(1) atoms. In the second Si site, Si(2) is bonded to six equivalent Y(1) atoms to form a mixture of distorted edge, corner, and face-sharing SiY6 pentagonal pyramids. is represented by the CIF file [CIF]
data_YSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.961
_cell_length_b   6.961
_cell_length_c   4.088
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   171.547
_cell_formula_units_Z   3
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  Y0  1  0.000  0.431  0.000  1.0
  Y  Y1  1  0.569  0.569  0.000  1.0
  Y  Y2  1  0.431  0.000  0.000  1.0
  Si  Si3  1  0.000  0.000  0.000  1.0
  Si  Si4  1  0.333  0.667  0.500  1.0
  Si  Si5  1  0.667  0.333  0.500  1.0
[/CIF]
.