The crystal structure described by Cr3Al9Si crystallizes in the hexagonal P6_3/mmc space group. Cr(1) is bonded to two equivalent Cr(1), two equivalent Al(1), six equivalent Al(2), and two equivalent Si(1) atoms to form distorted CrAl8Cr2Si2 cuboctahedra that share corners with four equivalent Cr(1)Al8Cr2Si2 cuboctahedra, faces with two equivalent Si(1)Al6Cr6 cuboctahedra, and faces with six equivalent Cr(1)Al8Cr2Si2 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 12-coordinate geometry to two equivalent Cr(1), two equivalent Al(1), and eight equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 13-coordinate geometry to three equivalent Cr(1), four equivalent Al(1), five equivalent Al(2), and one Si(1) atom. Si(1) is bonded to six equivalent Cr(1) and six equivalent Al(2) atoms to form SiAl6Cr6 cuboctahedra that share faces with two equivalent Si(1)Al6Cr6 cuboctahedra and faces with six equivalent Cr(1)Al8Cr2Si2 cuboctahedra. is represented by the CIF file [CIF]
data_Al9Cr3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.445
_cell_length_b   7.445
_cell_length_c   7.792
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   374.015
_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
  Al  Al0  1  0.457  0.914  0.250  1.0
  Al  Al1  1  0.543  0.086  0.750  1.0
  Al  Al2  1  0.086  0.543  0.250  1.0
  Al  Al3  1  0.914  0.457  0.750  1.0
  Al  Al4  1  0.457  0.543  0.250  1.0
  Al  Al5  1  0.543  0.457  0.750  1.0
  Al  Al6  1  0.202  0.403  0.562  1.0
  Al  Al7  1  0.798  0.597  0.438  1.0
  Al  Al8  1  0.597  0.798  0.562  1.0
  Al  Al9  1  0.798  0.597  0.062  1.0
  Al  Al10  1  0.403  0.202  0.438  1.0
  Al  Al11  1  0.202  0.403  0.938  1.0
  Al  Al12  1  0.202  0.798  0.562  1.0
  Al  Al13  1  0.403  0.202  0.062  1.0
  Al  Al14  1  0.798  0.202  0.438  1.0
  Al  Al15  1  0.597  0.798  0.938  1.0
  Al  Al16  1  0.798  0.202  0.062  1.0
  Al  Al17  1  0.202  0.798  0.938  1.0
  Cr  Cr18  1  0.115  0.230  0.250  1.0
  Cr  Cr19  1  0.885  0.770  0.750  1.0
  Cr  Cr20  1  0.770  0.885  0.250  1.0
  Cr  Cr21  1  0.230  0.115  0.750  1.0
  Cr  Cr22  1  0.115  0.885  0.250  1.0
  Cr  Cr23  1  0.885  0.115  0.750  1.0
  Si  Si24  1  0.000  0.000  1.000  1.0
  Si  Si25  1  0.000  0.000  0.500  1.0
[/CIF]
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The crystal structure described by Cr3Al9Si crystallizes in the hexagonal P6_3/mmc space group. Cr(1) is bonded to two equivalent Cr(1), two equivalent Al(1), six equivalent Al(2), and two equivalent Si(1) atoms to form distorted CrAl8Cr2Si2 cuboctahedra that share corners with four equivalent Cr(1)Al8Cr2Si2 cuboctahedra, faces with two equivalent Si(1)Al6Cr6 cuboctahedra, and faces with six equivalent Cr(1)Al8Cr2Si2 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 12-coordinate geometry to two equivalent Cr(1), two equivalent Al(1), and eight equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 13-coordinate geometry to three equivalent Cr(1), four equivalent Al(1), five equivalent Al(2), and one Si(1) atom. Si(1) is bonded to six equivalent Cr(1) and six equivalent Al(2) atoms to form SiAl6Cr6 cuboctahedra that share faces with two equivalent Si(1)Al6Cr6 cuboctahedra and faces with six equivalent Cr(1)Al8Cr2Si2 cuboctahedra. is represented by the CIF file [CIF]
data_Al9Cr3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.445
_cell_length_b   7.445
_cell_length_c   7.792
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   374.015
_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
  Al  Al0  1  0.457  0.914  0.250  1.0
  Al  Al1  1  0.543  0.086  0.750  1.0
  Al  Al2  1  0.086  0.543  0.250  1.0
  Al  Al3  1  0.914  0.457  0.750  1.0
  Al  Al4  1  0.457  0.543  0.250  1.0
  Al  Al5  1  0.543  0.457  0.750  1.0
  Al  Al6  1  0.202  0.403  0.562  1.0
  Al  Al7  1  0.798  0.597  0.438  1.0
  Al  Al8  1  0.597  0.798  0.562  1.0
  Al  Al9  1  0.798  0.597  0.062  1.0
  Al  Al10  1  0.403  0.202  0.438  1.0
  Al  Al11  1  0.202  0.403  0.938  1.0
  Al  Al12  1  0.202  0.798  0.562  1.0
  Al  Al13  1  0.403  0.202  0.062  1.0
  Al  Al14  1  0.798  0.202  0.438  1.0
  Al  Al15  1  0.597  0.798  0.938  1.0
  Al  Al16  1  0.798  0.202  0.062  1.0
  Al  Al17  1  0.202  0.798  0.938  1.0
  Cr  Cr18  1  0.115  0.230  0.250  1.0
  Cr  Cr19  1  0.885  0.770  0.750  1.0
  Cr  Cr20  1  0.770  0.885  0.250  1.0
  Cr  Cr21  1  0.230  0.115  0.750  1.0
  Cr  Cr22  1  0.115  0.885  0.250  1.0
  Cr  Cr23  1  0.885  0.115  0.750  1.0
  Si  Si24  1  0.000  0.000  1.000  1.0
  Si  Si25  1  0.000  0.000  0.500  1.0
[/CIF]
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