The compound described by CrAl3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Cr(1) is bonded to four equivalent Al(2) and eight equivalent Al(1) atoms to form CrAl12 cuboctahedra that share corners with four equivalent Cr(1)Al12 cuboctahedra, corners with eight equivalent Al(2)Al8Cr4 cuboctahedra, edges with eight equivalent Cr(1)Al12 cuboctahedra, edges with sixteen equivalent Al(1)Al8Cr4 cuboctahedra, faces with four equivalent Cr(1)Al12 cuboctahedra, faces with six equivalent Al(2)Al8Cr4 cuboctahedra, and faces with eight equivalent Al(1)Al8Cr4 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Cr(1), four equivalent Al(1), and four equivalent Al(2) atoms to form AlAl8Cr4 cuboctahedra that share corners with twelve equivalent Al(1)Al8Cr4 cuboctahedra, edges with eight equivalent Cr(1)Al12 cuboctahedra, edges with eight equivalent Al(1)Al8Cr4 cuboctahedra, edges with eight equivalent Al(2)Al8Cr4 cuboctahedra, faces with four equivalent Cr(1)Al12 cuboctahedra, faces with four equivalent Al(2)Al8Cr4 cuboctahedra, and faces with ten equivalent Al(1)Al8Cr4 cuboctahedra. In the second Al site, Al(2) is bonded to four equivalent Cr(1) and eight equivalent Al(1) atoms to form AlAl8Cr4 cuboctahedra that share corners with four equivalent Al(2)Al8Cr4 cuboctahedra, corners with eight equivalent Cr(1)Al12 cuboctahedra, edges with eight equivalent Al(2)Al8Cr4 cuboctahedra, edges with sixteen equivalent Al(1)Al8Cr4 cuboctahedra, faces with four equivalent Al(2)Al8Cr4 cuboctahedra, faces with six equivalent Cr(1)Al12 cuboctahedra, and faces with eight equivalent Al(1)Al8Cr4 cuboctahedra. is represented by the CIF file [CIF]
data_Al3Cr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.836
_cell_length_b   4.836
_cell_length_c   4.836
_cell_angle_alpha   133.747
_cell_angle_beta   133.747
_cell_angle_gamma   67.483
_symmetry_Int_Tables_number   1
_cell_volume   58.034
_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
  Al  Al0  1  0.750  0.250  0.500  1.0
  Al  Al1  1  0.250  0.750  0.500  1.0
  Al  Al2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
[/CIF]
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The compound described by CrAl3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Cr(1) is bonded to four equivalent Al(2) and eight equivalent Al(1) atoms to form CrAl12 cuboctahedra that share corners with four equivalent Cr(1)Al12 cuboctahedra, corners with eight equivalent Al(2)Al8Cr4 cuboctahedra, edges with eight equivalent Cr(1)Al12 cuboctahedra, edges with sixteen equivalent Al(1)Al8Cr4 cuboctahedra, faces with four equivalent Cr(1)Al12 cuboctahedra, faces with six equivalent Al(2)Al8Cr4 cuboctahedra, and faces with eight equivalent Al(1)Al8Cr4 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Cr(1), four equivalent Al(1), and four equivalent Al(2) atoms to form AlAl8Cr4 cuboctahedra that share corners with twelve equivalent Al(1)Al8Cr4 cuboctahedra, edges with eight equivalent Cr(1)Al12 cuboctahedra, edges with eight equivalent Al(1)Al8Cr4 cuboctahedra, edges with eight equivalent Al(2)Al8Cr4 cuboctahedra, faces with four equivalent Cr(1)Al12 cuboctahedra, faces with four equivalent Al(2)Al8Cr4 cuboctahedra, and faces with ten equivalent Al(1)Al8Cr4 cuboctahedra. In the second Al site, Al(2) is bonded to four equivalent Cr(1) and eight equivalent Al(1) atoms to form AlAl8Cr4 cuboctahedra that share corners with four equivalent Al(2)Al8Cr4 cuboctahedra, corners with eight equivalent Cr(1)Al12 cuboctahedra, edges with eight equivalent Al(2)Al8Cr4 cuboctahedra, edges with sixteen equivalent Al(1)Al8Cr4 cuboctahedra, faces with four equivalent Al(2)Al8Cr4 cuboctahedra, faces with six equivalent Cr(1)Al12 cuboctahedra, and faces with eight equivalent Al(1)Al8Cr4 cuboctahedra. is represented by the CIF file [CIF]
data_Al3Cr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.836
_cell_length_b   4.836
_cell_length_c   4.836
_cell_angle_alpha   133.747
_cell_angle_beta   133.747
_cell_angle_gamma   67.483
_symmetry_Int_Tables_number   1
_cell_volume   58.034
_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
  Al  Al0  1  0.750  0.250  0.500  1.0
  Al  Al1  1  0.250  0.750  0.500  1.0
  Al  Al2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
[/CIF]
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