The compound described by Cu15Si4 is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the cubic I-43d space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to eight equivalent Cu(2) and four equivalent Si(1) atoms to form CuCu8Si4 cuboctahedra that share corners with eight equivalent Si(1)Cu12 cuboctahedra, edges with eight equivalent Cu(1)Cu8Si4 cuboctahedra, and faces with four equivalent Si(1)Cu12 cuboctahedra. In the second Cu site, Cu(2) is bonded in a 13-coordinate geometry to two equivalent Cu(1), eight equivalent Cu(2), and three equivalent Si(1) atoms. Si(1) is bonded to three equivalent Cu(1) and nine equivalent Cu(2) atoms to form SiCu12 cuboctahedra that share corners with six equivalent Cu(1)Cu8Si4 cuboctahedra, edges with six equivalent Si(1)Cu12 cuboctahedra, faces with three equivalent Cu(1)Cu8Si4 cuboctahedra, and faces with five equivalent Si(1)Cu12 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu15Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.322
_cell_length_b   8.322
_cell_length_c   8.322
_cell_angle_alpha   109.471
_cell_angle_beta   109.471
_cell_angle_gamma   109.471
_symmetry_Int_Tables_number   1
_cell_volume   443.655
_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
  Cu  Cu0  1  0.250  0.625  0.375  1.0
  Cu  Cu1  1  0.375  0.250  0.625  1.0
  Cu  Cu2  1  0.125  0.750  0.875  1.0
  Cu  Cu3  1  0.875  0.125  0.750  1.0
  Cu  Cu4  1  0.625  0.375  0.250  1.0
  Cu  Cu5  1  0.750  0.875  0.125  1.0
  Cu  Cu6  1  0.124  0.073  0.275  1.0
  Cu  Cu7  1  0.927  0.702  0.051  1.0
  Cu  Cu8  1  0.150  0.876  0.449  1.0
  Cu  Cu9  1  0.449  0.150  0.876  1.0
  Cu  Cu10  1  0.725  0.350  0.798  1.0
  Cu  Cu11  1  0.798  0.725  0.350  1.0
  Cu  Cu12  1  0.702  0.051  0.927  1.0
  Cu  Cu13  1  0.850  0.225  0.298  1.0
  Cu  Cu14  1  0.551  0.202  0.427  1.0
  Cu  Cu15  1  0.650  0.949  0.376  1.0
  Cu  Cu16  1  0.225  0.298  0.850  1.0
  Cu  Cu17  1  0.427  0.551  0.202  1.0
  Cu  Cu18  1  0.949  0.376  0.650  1.0
  Cu  Cu19  1  0.275  0.124  0.073  1.0
  Cu  Cu20  1  0.073  0.275  0.124  1.0
  Cu  Cu21  1  0.298  0.850  0.225  1.0
  Cu  Cu22  1  0.202  0.427  0.551  1.0
  Cu  Cu23  1  0.376  0.650  0.949  1.0
  Cu  Cu24  1  0.573  0.624  0.775  1.0
  Cu  Cu25  1  0.775  0.573  0.624  1.0
  Cu  Cu26  1  0.624  0.775  0.573  1.0
  Cu  Cu27  1  0.350  0.798  0.725  1.0
  Cu  Cu28  1  0.051  0.927  0.702  1.0
  Cu  Cu29  1  0.876  0.449  0.150  1.0
  Si  Si30  1  0.412  0.412  0.412  1.0
  Si  Si31  1  0.588  0.500  0.000  1.0
  Si  Si32  1  0.000  0.588  0.500  1.0
  Si  Si33  1  0.500  0.000  0.588  1.0
  Si  Si34  1  0.000  0.088  0.500  1.0
  Si  Si35  1  0.500  0.000  0.088  1.0
  Si  Si36  1  0.088  0.500  0.000  1.0
  Si  Si37  1  0.912  0.912  0.912  1.0
[/CIF]
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The compound described by Cu15Si4 is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the cubic I-43d space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to eight equivalent Cu(2) and four equivalent Si(1) atoms to form CuCu8Si4 cuboctahedra that share corners with eight equivalent Si(1)Cu12 cuboctahedra, edges with eight equivalent Cu(1)Cu8Si4 cuboctahedra, and faces with four equivalent Si(1)Cu12 cuboctahedra. In the second Cu site, Cu(2) is bonded in a 13-coordinate geometry to two equivalent Cu(1), eight equivalent Cu(2), and three equivalent Si(1) atoms. Si(1) is bonded to three equivalent Cu(1) and nine equivalent Cu(2) atoms to form SiCu12 cuboctahedra that share corners with six equivalent Cu(1)Cu8Si4 cuboctahedra, edges with six equivalent Si(1)Cu12 cuboctahedra, faces with three equivalent Cu(1)Cu8Si4 cuboctahedra, and faces with five equivalent Si(1)Cu12 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu15Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.322
_cell_length_b   8.322
_cell_length_c   8.322
_cell_angle_alpha   109.471
_cell_angle_beta   109.471
_cell_angle_gamma   109.471
_symmetry_Int_Tables_number   1
_cell_volume   443.655
_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
  Cu  Cu0  1  0.250  0.625  0.375  1.0
  Cu  Cu1  1  0.375  0.250  0.625  1.0
  Cu  Cu2  1  0.125  0.750  0.875  1.0
  Cu  Cu3  1  0.875  0.125  0.750  1.0
  Cu  Cu4  1  0.625  0.375  0.250  1.0
  Cu  Cu5  1  0.750  0.875  0.125  1.0
  Cu  Cu6  1  0.124  0.073  0.275  1.0
  Cu  Cu7  1  0.927  0.702  0.051  1.0
  Cu  Cu8  1  0.150  0.876  0.449  1.0
  Cu  Cu9  1  0.449  0.150  0.876  1.0
  Cu  Cu10  1  0.725  0.350  0.798  1.0
  Cu  Cu11  1  0.798  0.725  0.350  1.0
  Cu  Cu12  1  0.702  0.051  0.927  1.0
  Cu  Cu13  1  0.850  0.225  0.298  1.0
  Cu  Cu14  1  0.551  0.202  0.427  1.0
  Cu  Cu15  1  0.650  0.949  0.376  1.0
  Cu  Cu16  1  0.225  0.298  0.850  1.0
  Cu  Cu17  1  0.427  0.551  0.202  1.0
  Cu  Cu18  1  0.949  0.376  0.650  1.0
  Cu  Cu19  1  0.275  0.124  0.073  1.0
  Cu  Cu20  1  0.073  0.275  0.124  1.0
  Cu  Cu21  1  0.298  0.850  0.225  1.0
  Cu  Cu22  1  0.202  0.427  0.551  1.0
  Cu  Cu23  1  0.376  0.650  0.949  1.0
  Cu  Cu24  1  0.573  0.624  0.775  1.0
  Cu  Cu25  1  0.775  0.573  0.624  1.0
  Cu  Cu26  1  0.624  0.775  0.573  1.0
  Cu  Cu27  1  0.350  0.798  0.725  1.0
  Cu  Cu28  1  0.051  0.927  0.702  1.0
  Cu  Cu29  1  0.876  0.449  0.150  1.0
  Si  Si30  1  0.412  0.412  0.412  1.0
  Si  Si31  1  0.588  0.500  0.000  1.0
  Si  Si32  1  0.000  0.588  0.500  1.0
  Si  Si33  1  0.500  0.000  0.588  1.0
  Si  Si34  1  0.000  0.088  0.500  1.0
  Si  Si35  1  0.500  0.000  0.088  1.0
  Si  Si36  1  0.088  0.500  0.000  1.0
  Si  Si37  1  0.912  0.912  0.912  1.0
[/CIF]
.