The structure described by Ba4Cu3Si20 crystallizes in the cubic Pm-3n space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 20-coordinate geometry to eight equivalent Si(2) and twelve equivalent Si(1) atoms. In the second Ba site, Ba(2) is bonded in a 20-coordinate geometry to four equivalent Cu(1), eight equivalent Si(1), and eight equivalent Si(2) atoms. Cu(1) is bonded to four equivalent Ba(2) and four equivalent Si(1) atoms to form a mixture of distorted corner and edge-sharing CuBa4Si4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a 5-coordinate geometry to one Ba(1), three equivalent Ba(2), one Si(2), and three equivalent Si(1) atoms. In the second Si site, Si(1) is bonded in a 7-coordinate geometry to one Ba(1), two equivalent Ba(2), one Cu(1), one Si(1), and two equivalent Si(2) atoms. is represented by the CIF card [CIF]
data_Ba4Cu3Si20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.344
_cell_length_b   10.344
_cell_length_c   10.344
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1106.673
_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
  Ba  Ba0  1  0.000  1.000  1.000  1.0
  Ba  Ba1  1  0.500  0.500  0.500  1.0
  Ba  Ba2  1  0.250  1.000  0.500  1.0
  Ba  Ba3  1  0.750  1.000  0.500  1.0
  Ba  Ba4  1  0.500  0.250  1.000  1.0
  Ba  Ba5  1  0.500  0.750  1.000  1.0
  Ba  Ba6  1  0.000  0.500  0.250  1.0
  Ba  Ba7  1  0.000  0.500  0.750  1.0
  Cu  Cu8  1  0.250  0.500  1.000  1.0
  Cu  Cu9  1  0.750  0.500  1.000  1.0
  Cu  Cu10  1  0.000  0.250  0.500  1.0
  Cu  Cu11  1  0.000  0.750  0.500  1.0
  Cu  Cu12  1  0.500  1.000  0.250  1.0
  Cu  Cu13  1  0.500  1.000  0.750  1.0
  Si  Si14  1  0.000  0.120  0.311  1.0
  Si  Si15  1  0.000  0.880  0.689  1.0
  Si  Si16  1  0.000  0.880  0.311  1.0
  Si  Si17  1  0.000  0.120  0.689  1.0
  Si  Si18  1  0.311  1.000  0.120  1.0
  Si  Si19  1  0.620  0.500  0.189  1.0
  Si  Si20  1  0.689  1.000  0.880  1.0
  Si  Si21  1  0.380  0.500  0.811  1.0
  Si  Si22  1  0.311  1.000  0.880  1.0
  Si  Si23  1  0.380  0.500  0.189  1.0
  Si  Si24  1  0.689  1.000  0.120  1.0
  Si  Si25  1  0.620  0.500  0.811  1.0
  Si  Si26  1  0.120  0.311  1.000  1.0
  Si  Si27  1  0.500  0.811  0.380  1.0
  Si  Si28  1  0.880  0.689  1.000  1.0
  Si  Si29  1  0.500  0.189  0.620  1.0
  Si  Si30  1  0.120  0.689  1.000  1.0
  Si  Si31  1  0.500  0.189  0.380  1.0
  Si  Si32  1  0.880  0.311  1.000  1.0
  Si  Si33  1  0.500  0.811  0.620  1.0
  Si  Si34  1  0.189  0.620  0.500  1.0
  Si  Si35  1  0.811  0.380  0.500  1.0
  Si  Si36  1  0.189  0.380  0.500  1.0
  Si  Si37  1  0.811  0.620  0.500  1.0
  Si  Si38  1  0.184  0.184  0.184  1.0
  Si  Si39  1  0.816  0.816  0.816  1.0
  Si  Si40  1  0.816  0.816  0.184  1.0
  Si  Si41  1  0.816  0.184  0.816  1.0
  Si  Si42  1  0.684  0.684  0.316  1.0
  Si  Si43  1  0.184  0.184  0.816  1.0
  Si  Si44  1  0.184  0.816  0.184  1.0
  Si  Si45  1  0.316  0.316  0.684  1.0
  Si  Si46  1  0.184  0.816  0.816  1.0
  Si  Si47  1  0.316  0.316  0.316  1.0
  Si  Si48  1  0.816  0.184  0.184  1.0
  Si  Si49  1  0.684  0.684  0.684  1.0
  Si  Si50  1  0.684  0.316  0.684  1.0
  Si  Si51  1  0.316  0.684  0.316  1.0
  Si  Si52  1  0.316  0.684  0.684  1.0
  Si  Si53  1  0.684  0.316  0.316  1.0
[/CIF]
.
The structure described by Ba4Cu3Si20 crystallizes in the cubic Pm-3n space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 20-coordinate geometry to eight equivalent Si(2) and twelve equivalent Si(1) atoms. In the second Ba site, Ba(2) is bonded in a 20-coordinate geometry to four equivalent Cu(1), eight equivalent Si(1), and eight equivalent Si(2) atoms. Cu(1) is bonded to four equivalent Ba(2) and four equivalent Si(1) atoms to form a mixture of distorted corner and edge-sharing CuBa4Si4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a 5-coordinate geometry to one Ba(1), three equivalent Ba(2), one Si(2), and three equivalent Si(1) atoms. In the second Si site, Si(1) is bonded in a 7-coordinate geometry to one Ba(1), two equivalent Ba(2), one Cu(1), one Si(1), and two equivalent Si(2) atoms. is represented by the CIF card [CIF]
data_Ba4Cu3Si20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.344
_cell_length_b   10.344
_cell_length_c   10.344
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1106.673
_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
  Ba  Ba0  1  0.000  1.000  1.000  1.0
  Ba  Ba1  1  0.500  0.500  0.500  1.0
  Ba  Ba2  1  0.250  1.000  0.500  1.0
  Ba  Ba3  1  0.750  1.000  0.500  1.0
  Ba  Ba4  1  0.500  0.250  1.000  1.0
  Ba  Ba5  1  0.500  0.750  1.000  1.0
  Ba  Ba6  1  0.000  0.500  0.250  1.0
  Ba  Ba7  1  0.000  0.500  0.750  1.0
  Cu  Cu8  1  0.250  0.500  1.000  1.0
  Cu  Cu9  1  0.750  0.500  1.000  1.0
  Cu  Cu10  1  0.000  0.250  0.500  1.0
  Cu  Cu11  1  0.000  0.750  0.500  1.0
  Cu  Cu12  1  0.500  1.000  0.250  1.0
  Cu  Cu13  1  0.500  1.000  0.750  1.0
  Si  Si14  1  0.000  0.120  0.311  1.0
  Si  Si15  1  0.000  0.880  0.689  1.0
  Si  Si16  1  0.000  0.880  0.311  1.0
  Si  Si17  1  0.000  0.120  0.689  1.0
  Si  Si18  1  0.311  1.000  0.120  1.0
  Si  Si19  1  0.620  0.500  0.189  1.0
  Si  Si20  1  0.689  1.000  0.880  1.0
  Si  Si21  1  0.380  0.500  0.811  1.0
  Si  Si22  1  0.311  1.000  0.880  1.0
  Si  Si23  1  0.380  0.500  0.189  1.0
  Si  Si24  1  0.689  1.000  0.120  1.0
  Si  Si25  1  0.620  0.500  0.811  1.0
  Si  Si26  1  0.120  0.311  1.000  1.0
  Si  Si27  1  0.500  0.811  0.380  1.0
  Si  Si28  1  0.880  0.689  1.000  1.0
  Si  Si29  1  0.500  0.189  0.620  1.0
  Si  Si30  1  0.120  0.689  1.000  1.0
  Si  Si31  1  0.500  0.189  0.380  1.0
  Si  Si32  1  0.880  0.311  1.000  1.0
  Si  Si33  1  0.500  0.811  0.620  1.0
  Si  Si34  1  0.189  0.620  0.500  1.0
  Si  Si35  1  0.811  0.380  0.500  1.0
  Si  Si36  1  0.189  0.380  0.500  1.0
  Si  Si37  1  0.811  0.620  0.500  1.0
  Si  Si38  1  0.184  0.184  0.184  1.0
  Si  Si39  1  0.816  0.816  0.816  1.0
  Si  Si40  1  0.816  0.816  0.184  1.0
  Si  Si41  1  0.816  0.184  0.816  1.0
  Si  Si42  1  0.684  0.684  0.316  1.0
  Si  Si43  1  0.184  0.184  0.816  1.0
  Si  Si44  1  0.184  0.816  0.184  1.0
  Si  Si45  1  0.316  0.316  0.684  1.0
  Si  Si46  1  0.184  0.816  0.816  1.0
  Si  Si47  1  0.316  0.316  0.316  1.0
  Si  Si48  1  0.816  0.184  0.184  1.0
  Si  Si49  1  0.684  0.684  0.684  1.0
  Si  Si50  1  0.684  0.316  0.684  1.0
  Si  Si51  1  0.316  0.684  0.316  1.0
  Si  Si52  1  0.316  0.684  0.684  1.0
  Si  Si53  1  0.684  0.316  0.316  1.0
[/CIF]
.