The crystal structure described by Au4Cu crystallizes in the trigonal R-3m space group. There are two inequivalent Au sites. In the first Au site, Au(1) is bonded in a 3-coordinate geometry to three equivalent Au(2) and three equivalent Cu(1) atoms. In the second Au site, Au(2) is bonded to three equivalent Au(1) and nine equivalent Au(2) atoms to form a mixture of edge, face, and corner-sharing AuAu12 cuboctahedra. Cu(1) is bonded in a 6-coordinate geometry to six equivalent Au(1) atoms. is represented by the CIF file [CIF]
data_CuAu4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.571
_cell_length_b   11.571
_cell_length_c   11.571
_cell_angle_alpha   14.550
_cell_angle_beta   14.550
_cell_angle_gamma   14.550
_symmetry_Int_Tables_number   1
_cell_volume   85.123
_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
  Cu  Cu0  1  0.000  0.000  0.000  1.0
  Au  Au1  1  0.606  0.606  0.606  1.0
  Au  Au2  1  0.202  0.202  0.202  1.0
  Au  Au3  1  0.798  0.798  0.798  1.0
  Au  Au4  1  0.394  0.394  0.394  1.0
[/CIF]
.
The crystal structure described by Au4Cu crystallizes in the trigonal R-3m space group. There are two inequivalent Au sites. In the first Au site, Au(1) is bonded in a 3-coordinate geometry to three equivalent Au(2) and three equivalent Cu(1) atoms. In the second Au site, Au(2) is bonded to three equivalent Au(1) and nine equivalent Au(2) atoms to form a mixture of edge, face, and corner-sharing AuAu12 cuboctahedra. Cu(1) is bonded in a 6-coordinate geometry to six equivalent Au(1) atoms. is represented by the CIF file [CIF]
data_CuAu4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.571
_cell_length_b   11.571
_cell_length_c   11.571
_cell_angle_alpha   14.550
_cell_angle_beta   14.550
_cell_angle_gamma   14.550
_symmetry_Int_Tables_number   1
_cell_volume   85.123
_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
  Cu  Cu0  1  0.000  0.000  0.000  1.0
  Au  Au1  1  0.606  0.606  0.606  1.0
  Au  Au2  1  0.202  0.202  0.202  1.0
  Au  Au3  1  0.798  0.798  0.798  1.0
  Au  Au4  1  0.394  0.394  0.394  1.0
[/CIF]
.