The crystal structure described by Er15Si9C crystallizes in the hexagonal P6_3mc space group. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. In the second Er site, Er(2) is bonded in a 1-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and one C(1) atom. In the third Er site, Er(3) is bonded in a 1-coordinate geometry to one Si(1), two equivalent Si(2), two equivalent Si(3), and one C(1) atom. In the fourth Er site, Er(4) is bonded in a 5-coordinate geometry to one Si(3) and four equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(2) is bonded in a 8-coordinate geometry to two equivalent Er(2), two equivalent Er(3), and four equivalent Er(1) atoms. In the second Si site, Si(3) is bonded in a 9-coordinate geometry to one Er(4), two equivalent Er(2), two equivalent Er(3), and four equivalent Er(1) atoms. In the third Si site, Si(1) is bonded in a 9-coordinate geometry to one Er(3), four equivalent Er(1), and four equivalent Er(4) atoms. C(1) is bonded in an octahedral geometry to three equivalent Er(2) and three equivalent Er(3) atoms. is represented by the CIF card [CIF]
data_Er15Si9C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.522
_cell_length_b   14.522
_cell_length_c   6.283
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   1147.424
_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
  Er  Er0  1  0.990  0.329  0.500  1.0
  Er  Er1  1  0.671  0.661  0.500  1.0
  Er  Er2  1  0.339  0.010  0.500  1.0
  Er  Er3  1  0.671  0.010  0.500  1.0
  Er  Er4  1  0.339  0.329  0.500  1.0
  Er  Er5  1  0.990  0.661  0.500  1.0
  Er  Er6  1  0.010  0.671  1.000  1.0
  Er  Er7  1  0.329  0.339  1.000  1.0
  Er  Er8  1  0.661  0.990  1.000  1.0
  Er  Er9  1  0.329  0.990  1.000  1.0
  Er  Er10  1  0.661  0.671  1.000  1.0
  Er  Er11  1  0.010  0.339  1.000  1.0
  Er  Er12  1  0.588  0.412  0.212  1.0
  Er  Er13  1  0.588  0.175  0.212  1.0
  Er  Er14  1  0.825  0.412  0.212  1.0
  Er  Er15  1  0.412  0.588  0.712  1.0
  Er  Er16  1  0.412  0.825  0.712  1.0
  Er  Er17  1  0.175  0.588  0.712  1.0
  Er  Er18  1  0.746  0.254  0.765  1.0
  Er  Er19  1  0.746  0.492  0.765  1.0
  Er  Er20  1  0.508  0.254  0.765  1.0
  Er  Er21  1  0.254  0.746  0.265  1.0
  Er  Er22  1  0.254  0.508  0.265  1.0
  Er  Er23  1  0.492  0.746  0.265  1.0
  Er  Er24  1  0.919  0.081  0.243  1.0
  Er  Er25  1  0.919  0.838  0.243  1.0
  Er  Er26  1  0.162  0.081  0.243  1.0
  Er  Er27  1  0.081  0.919  0.743  1.0
  Er  Er28  1  0.081  0.162  0.743  1.0
  Er  Er29  1  0.838  0.919  0.743  1.0
  Si  Si30  1  0.868  0.132  0.766  1.0
  Si  Si31  1  0.868  0.736  0.766  1.0
  Si  Si32  1  0.264  0.132  0.766  1.0
  Si  Si33  1  0.132  0.868  0.266  1.0
  Si  Si34  1  0.132  0.264  0.266  1.0
  Si  Si35  1  0.736  0.868  0.266  1.0
  Si  Si36  1  0.533  0.467  0.760  1.0
  Si  Si37  1  0.533  0.066  0.760  1.0
  Si  Si38  1  0.934  0.467  0.760  1.0
  Si  Si39  1  0.467  0.533  0.260  1.0
  Si  Si40  1  0.467  0.934  0.260  1.0
  Si  Si41  1  0.066  0.533  0.260  1.0
  Si  Si42  1  0.800  0.200  0.227  1.0
  Si  Si43  1  0.800  0.601  0.227  1.0
  Si  Si44  1  0.399  0.200  0.227  1.0
  Si  Si45  1  0.200  0.800  0.727  1.0
  Si  Si46  1  0.200  0.399  0.727  1.0
  Si  Si47  1  0.601  0.800  0.727  1.0
  C  C48  1  0.667  0.333  0.986  1.0
  C  C49  1  0.333  0.667  0.486  1.0
[/CIF]
.
The crystal structure described by Er15Si9C crystallizes in the hexagonal P6_3mc space group. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. In the second Er site, Er(2) is bonded in a 1-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and one C(1) atom. In the third Er site, Er(3) is bonded in a 1-coordinate geometry to one Si(1), two equivalent Si(2), two equivalent Si(3), and one C(1) atom. In the fourth Er site, Er(4) is bonded in a 5-coordinate geometry to one Si(3) and four equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(2) is bonded in a 8-coordinate geometry to two equivalent Er(2), two equivalent Er(3), and four equivalent Er(1) atoms. In the second Si site, Si(3) is bonded in a 9-coordinate geometry to one Er(4), two equivalent Er(2), two equivalent Er(3), and four equivalent Er(1) atoms. In the third Si site, Si(1) is bonded in a 9-coordinate geometry to one Er(3), four equivalent Er(1), and four equivalent Er(4) atoms. C(1) is bonded in an octahedral geometry to three equivalent Er(2) and three equivalent Er(3) atoms. is represented by the CIF card [CIF]
data_Er15Si9C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.522
_cell_length_b   14.522
_cell_length_c   6.283
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   1147.424
_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
  Er  Er0  1  0.990  0.329  0.500  1.0
  Er  Er1  1  0.671  0.661  0.500  1.0
  Er  Er2  1  0.339  0.010  0.500  1.0
  Er  Er3  1  0.671  0.010  0.500  1.0
  Er  Er4  1  0.339  0.329  0.500  1.0
  Er  Er5  1  0.990  0.661  0.500  1.0
  Er  Er6  1  0.010  0.671  1.000  1.0
  Er  Er7  1  0.329  0.339  1.000  1.0
  Er  Er8  1  0.661  0.990  1.000  1.0
  Er  Er9  1  0.329  0.990  1.000  1.0
  Er  Er10  1  0.661  0.671  1.000  1.0
  Er  Er11  1  0.010  0.339  1.000  1.0
  Er  Er12  1  0.588  0.412  0.212  1.0
  Er  Er13  1  0.588  0.175  0.212  1.0
  Er  Er14  1  0.825  0.412  0.212  1.0
  Er  Er15  1  0.412  0.588  0.712  1.0
  Er  Er16  1  0.412  0.825  0.712  1.0
  Er  Er17  1  0.175  0.588  0.712  1.0
  Er  Er18  1  0.746  0.254  0.765  1.0
  Er  Er19  1  0.746  0.492  0.765  1.0
  Er  Er20  1  0.508  0.254  0.765  1.0
  Er  Er21  1  0.254  0.746  0.265  1.0
  Er  Er22  1  0.254  0.508  0.265  1.0
  Er  Er23  1  0.492  0.746  0.265  1.0
  Er  Er24  1  0.919  0.081  0.243  1.0
  Er  Er25  1  0.919  0.838  0.243  1.0
  Er  Er26  1  0.162  0.081  0.243  1.0
  Er  Er27  1  0.081  0.919  0.743  1.0
  Er  Er28  1  0.081  0.162  0.743  1.0
  Er  Er29  1  0.838  0.919  0.743  1.0
  Si  Si30  1  0.868  0.132  0.766  1.0
  Si  Si31  1  0.868  0.736  0.766  1.0
  Si  Si32  1  0.264  0.132  0.766  1.0
  Si  Si33  1  0.132  0.868  0.266  1.0
  Si  Si34  1  0.132  0.264  0.266  1.0
  Si  Si35  1  0.736  0.868  0.266  1.0
  Si  Si36  1  0.533  0.467  0.760  1.0
  Si  Si37  1  0.533  0.066  0.760  1.0
  Si  Si38  1  0.934  0.467  0.760  1.0
  Si  Si39  1  0.467  0.533  0.260  1.0
  Si  Si40  1  0.467  0.934  0.260  1.0
  Si  Si41  1  0.066  0.533  0.260  1.0
  Si  Si42  1  0.800  0.200  0.227  1.0
  Si  Si43  1  0.800  0.601  0.227  1.0
  Si  Si44  1  0.399  0.200  0.227  1.0
  Si  Si45  1  0.200  0.800  0.727  1.0
  Si  Si46  1  0.200  0.399  0.727  1.0
  Si  Si47  1  0.601  0.800  0.727  1.0
  C  C48  1  0.667  0.333  0.986  1.0
  C  C49  1  0.333  0.667  0.486  1.0
[/CIF]
.