The crystal structure described by Ho15Si9C crystallizes in the hexagonal P6_3mc space group. There are four inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 2-coordinate geometry to one Si(2), three equivalent Si(1), and two equivalent C(1) atoms. In the second Ho site, Ho(2) is bonded in a 4-coordinate geometry to one Si(1), one Si(2), and two equivalent Si(3) atoms. In the third Ho site, Ho(3) is bonded in a 5-coordinate geometry to two equivalent Si(2) and three equivalent Si(3) atoms. In the fourth Ho site, Ho(4) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(2) is bonded in a 8-coordinate geometry to one Ho(1), one Ho(2), two equivalent Ho(3), and four equivalent Ho(4) atoms. In the second Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Ho(2), three equivalent Ho(3), and four equivalent Ho(4) atoms. In the third Si site, Si(1) is bonded in a 8-coordinate geometry to one Ho(2), three equivalent Ho(1), and four equivalent Ho(4) atoms. C(1) is bonded to six equivalent Ho(1) atoms to form face-sharing CHo6 octahedra. is represented by the CIF file [CIF]
data_Ho15Si9C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.578
_cell_length_b   14.578
_cell_length_c   6.355
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   1169.633
_cell_formula_units_Z   2
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
  Ho  Ho0  1  0.074  0.148  0.770  1.0
  Ho  Ho1  1  0.074  0.926  0.770  1.0
  Ho  Ho2  1  0.852  0.926  0.770  1.0
  Ho  Ho3  1  0.926  0.852  0.270  1.0
  Ho  Ho4  1  0.926  0.074  0.270  1.0
  Ho  Ho5  1  0.148  0.074  0.270  1.0
  Ho  Ho6  1  0.252  0.503  0.239  1.0
  Ho  Ho7  1  0.252  0.748  0.239  1.0
  Ho  Ho8  1  0.497  0.748  0.239  1.0
  Ho  Ho9  1  0.748  0.497  0.739  1.0
  Ho  Ho10  1  0.748  0.252  0.739  1.0
  Ho  Ho11  1  0.503  0.252  0.739  1.0
  Ho  Ho12  1  0.416  0.831  0.761  1.0
  Ho  Ho13  1  0.416  0.584  0.761  1.0
  Ho  Ho14  1  0.169  0.584  0.761  1.0
  Ho  Ho15  1  0.584  0.169  0.261  1.0
  Ho  Ho16  1  0.584  0.416  0.261  1.0
  Ho  Ho17  1  0.831  0.416  0.261  1.0
  Ho  Ho18  1  0.013  0.338  0.504  1.0
  Ho  Ho19  1  0.326  0.987  0.504  1.0
  Ho  Ho20  1  0.662  0.674  0.504  1.0
  Ho  Ho21  1  0.326  0.338  0.504  1.0
  Ho  Ho22  1  0.662  0.987  0.504  1.0
  Ho  Ho23  1  0.013  0.674  0.504  1.0
  Ho  Ho24  1  0.987  0.662  0.004  1.0
  Ho  Ho25  1  0.674  0.013  0.004  1.0
  Ho  Ho26  1  0.338  0.326  0.004  1.0
  Ho  Ho27  1  0.674  0.662  0.004  1.0
  Ho  Ho28  1  0.338  0.013  0.004  1.0
  Ho  Ho29  1  0.987  0.326  0.004  1.0
  Si  Si30  1  0.136  0.272  0.234  1.0
  Si  Si31  1  0.136  0.864  0.234  1.0
  Si  Si32  1  0.728  0.864  0.234  1.0
  Si  Si33  1  0.864  0.728  0.734  1.0
  Si  Si34  1  0.864  0.136  0.734  1.0
  Si  Si35  1  0.272  0.136  0.734  1.0
  Si  Si36  1  0.202  0.404  0.784  1.0
  Si  Si37  1  0.202  0.798  0.784  1.0
  Si  Si38  1  0.596  0.798  0.784  1.0
  Si  Si39  1  0.798  0.596  0.284  1.0
  Si  Si40  1  0.798  0.202  0.284  1.0
  Si  Si41  1  0.404  0.202  0.284  1.0
  Si  Si42  1  0.466  0.931  0.243  1.0
  Si  Si43  1  0.466  0.534  0.243  1.0
  Si  Si44  1  0.069  0.534  0.243  1.0
  Si  Si45  1  0.534  0.069  0.743  1.0
  Si  Si46  1  0.534  0.466  0.743  1.0
  Si  Si47  1  0.931  0.466  0.743  1.0
  C  C48  1  0.000  0.000  0.017  1.0
  C  C49  1  0.000  0.000  0.517  1.0
[/CIF]
.
The crystal structure described by Ho15Si9C crystallizes in the hexagonal P6_3mc space group. There are four inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 2-coordinate geometry to one Si(2), three equivalent Si(1), and two equivalent C(1) atoms. In the second Ho site, Ho(2) is bonded in a 4-coordinate geometry to one Si(1), one Si(2), and two equivalent Si(3) atoms. In the third Ho site, Ho(3) is bonded in a 5-coordinate geometry to two equivalent Si(2) and three equivalent Si(3) atoms. In the fourth Ho site, Ho(4) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(2) is bonded in a 8-coordinate geometry to one Ho(1), one Ho(2), two equivalent Ho(3), and four equivalent Ho(4) atoms. In the second Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Ho(2), three equivalent Ho(3), and four equivalent Ho(4) atoms. In the third Si site, Si(1) is bonded in a 8-coordinate geometry to one Ho(2), three equivalent Ho(1), and four equivalent Ho(4) atoms. C(1) is bonded to six equivalent Ho(1) atoms to form face-sharing CHo6 octahedra. is represented by the CIF file [CIF]
data_Ho15Si9C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.578
_cell_length_b   14.578
_cell_length_c   6.355
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   1169.633
_cell_formula_units_Z   2
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
  Ho  Ho0  1  0.074  0.148  0.770  1.0
  Ho  Ho1  1  0.074  0.926  0.770  1.0
  Ho  Ho2  1  0.852  0.926  0.770  1.0
  Ho  Ho3  1  0.926  0.852  0.270  1.0
  Ho  Ho4  1  0.926  0.074  0.270  1.0
  Ho  Ho5  1  0.148  0.074  0.270  1.0
  Ho  Ho6  1  0.252  0.503  0.239  1.0
  Ho  Ho7  1  0.252  0.748  0.239  1.0
  Ho  Ho8  1  0.497  0.748  0.239  1.0
  Ho  Ho9  1  0.748  0.497  0.739  1.0
  Ho  Ho10  1  0.748  0.252  0.739  1.0
  Ho  Ho11  1  0.503  0.252  0.739  1.0
  Ho  Ho12  1  0.416  0.831  0.761  1.0
  Ho  Ho13  1  0.416  0.584  0.761  1.0
  Ho  Ho14  1  0.169  0.584  0.761  1.0
  Ho  Ho15  1  0.584  0.169  0.261  1.0
  Ho  Ho16  1  0.584  0.416  0.261  1.0
  Ho  Ho17  1  0.831  0.416  0.261  1.0
  Ho  Ho18  1  0.013  0.338  0.504  1.0
  Ho  Ho19  1  0.326  0.987  0.504  1.0
  Ho  Ho20  1  0.662  0.674  0.504  1.0
  Ho  Ho21  1  0.326  0.338  0.504  1.0
  Ho  Ho22  1  0.662  0.987  0.504  1.0
  Ho  Ho23  1  0.013  0.674  0.504  1.0
  Ho  Ho24  1  0.987  0.662  0.004  1.0
  Ho  Ho25  1  0.674  0.013  0.004  1.0
  Ho  Ho26  1  0.338  0.326  0.004  1.0
  Ho  Ho27  1  0.674  0.662  0.004  1.0
  Ho  Ho28  1  0.338  0.013  0.004  1.0
  Ho  Ho29  1  0.987  0.326  0.004  1.0
  Si  Si30  1  0.136  0.272  0.234  1.0
  Si  Si31  1  0.136  0.864  0.234  1.0
  Si  Si32  1  0.728  0.864  0.234  1.0
  Si  Si33  1  0.864  0.728  0.734  1.0
  Si  Si34  1  0.864  0.136  0.734  1.0
  Si  Si35  1  0.272  0.136  0.734  1.0
  Si  Si36  1  0.202  0.404  0.784  1.0
  Si  Si37  1  0.202  0.798  0.784  1.0
  Si  Si38  1  0.596  0.798  0.784  1.0
  Si  Si39  1  0.798  0.596  0.284  1.0
  Si  Si40  1  0.798  0.202  0.284  1.0
  Si  Si41  1  0.404  0.202  0.284  1.0
  Si  Si42  1  0.466  0.931  0.243  1.0
  Si  Si43  1  0.466  0.534  0.243  1.0
  Si  Si44  1  0.069  0.534  0.243  1.0
  Si  Si45  1  0.534  0.069  0.743  1.0
  Si  Si46  1  0.534  0.466  0.743  1.0
  Si  Si47  1  0.931  0.466  0.743  1.0
  C  C48  1  0.000  0.000  0.017  1.0
  C  C49  1  0.000  0.000  0.517  1.0
[/CIF]
.