The crystal structure described by Ba8CuSi16 is Magnesium tetraboride-derived structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one Cu(1), one Si(10), one Si(11), one Si(13), one Si(14), one Si(16), one Si(2), one Si(4), one Si(5), and one Si(8) atom. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one Si(12), one Si(15), one Si(3), one Si(6), one Si(7), one Si(9), and two equivalent Si(1) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one Cu(1), one Si(12), one Si(15), one Si(2), one Si(4), one Si(6), one Si(7), and one Si(9) atom. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to one Si(1), one Si(10), one Si(11), one Si(14), one Si(16), one Si(3), one Si(5), and one Si(8) atom. In the fifth Ba site, Ba(5) is bonded in a 10-coordinate geometry to one Si(1), one Si(11), one Si(12), one Si(13), one Si(14), one Si(15), one Si(5), one Si(9), and two equivalent Si(7) atoms. In the sixth Ba site, Ba(6) is bonded in a 8-coordinate geometry to one Cu(1), one Si(10), one Si(14), one Si(16), one Si(2), one Si(4), one Si(6), and two equivalent Si(8) atoms. In the seventh Ba site, Ba(7) is bonded in a 7-coordinate geometry to one Si(10), one Si(13), one Si(15), one Si(16), one Si(3), one Si(7), one Si(9), and two equivalent Si(5) atoms. In the eighth Ba site, Ba(8) is bonded in a 9-coordinate geometry to one Cu(1), one Si(10), one Si(12), one Si(15), one Si(16), one Si(8), one Si(9), and two equivalent Si(6) atoms. Cu(1) is bonded in a 8-coordinate geometry to one Ba(1), one Ba(3), one Ba(6), one Ba(8), one Si(10), one Si(2), one Si(4), and one Si(6) atom. There are sixteen inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Ba(4), one Ba(5), two equivalent Ba(2), one Si(15), one Si(5), and one Si(9) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Ba(1), one Ba(3), one Ba(6), one Cu(1), one Si(10), one Si(16), and one Si(6) atom. In the third Si site, Si(3) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(4), one Ba(7), one Si(11), one Si(13), one Si(14), and one Si(7) atom. In the fourth Si site, Si(4) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(6), one Cu(1), one Si(12), and one Si(8) atom. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Ba(1), one Ba(4), one Ba(5), two equivalent Ba(7), one Si(1), one Si(15), and one Si(9) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Ba(2), one Ba(3), one Ba(6), two equivalent Ba(8), one Cu(1), one Si(10), one Si(16), and one Si(2) atom. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Ba(2), one Ba(3), one Ba(7), two equivalent Ba(5), one Si(11), one Si(13), and one Si(3) atom. In the eighth Si site, Si(8) is bonded to one Ba(1), one Ba(4), one Ba(8), two equivalent Ba(6), one Si(12), and one Si(4) atom to form distorted SiBa5Si2 pentagonal bipyramids that share  a cornercorner with one Si(14)Ba4Si2 octahedra, corners with two equivalent Si(8)Ba5Si2 pentagonal bipyramids, and  a faceface with one Si(14)Ba4Si2 octahedra. The corner-sharing octahedral tilt angles are 54°. In the ninth Si site, Si(9) is bonded in a 8-coordinate geometry to one Ba(2), one Ba(3), one Ba(5), one Ba(7), one Ba(8), one Si(1), one Si(15), and one Si(5) atom. In the tenth Si site, Si(10) is bonded in a 9-coordinate geometry to one Ba(1), one Ba(4), one Ba(6), one Ba(7), one Ba(8), one Cu(1), one Si(16), one Si(2), and one Si(6) atom. In the eleventh Si site, Si(11) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(4), one Ba(5), one Si(13), one Si(3), and one Si(7) atom. In the twelfth Si site, Si(12) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), one Ba(5), one Ba(8), one Si(4), and one Si(8) atom. In the thirteenth Si site, Si(13) is bonded in a 7-coordinate geometry to one Ba(1), one Ba(5), one Ba(7), one Si(11), one Si(14), one Si(3), and one Si(7) atom. In the fourteenth Si site, Si(14) is bonded to one Ba(1), one Ba(4), one Ba(5), one Ba(6), one Si(13), and one Si(3) atom to form a mixture of distorted face and corner-sharing SiBa4Si2 octahedra. In the fifteenth Si site, Si(15) is bonded in a 8-coordinate geometry to one Ba(2), one Ba(3), one Ba(5), one Ba(7), one Ba(8), one Si(1), one Si(5), and one Si(9) atom. In the sixteenth Si site, Si(16) is bonded in a 8-coordinate geometry to one Ba(1), one Ba(4), one Ba(6), one Ba(7), one Ba(8), one Si(10), one Si(2), and one Si(6) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba8CuSi16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.907
_cell_length_b   9.060
_cell_length_c   11.908
_cell_angle_alpha   89.638
_cell_angle_beta   89.644
_cell_angle_gamma   85.726
_symmetry_Int_Tables_number   1
_cell_volume   743.032
_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
  Ba  Ba0  1  0.731  0.989  0.717  1.0
  Ba  Ba1  1  0.272  0.504  0.194  1.0
  Ba  Ba2  1  0.312  0.990  0.289  1.0
  Ba  Ba3  1  0.666  0.468  0.789  1.0
  Ba  Ba4  1  0.790  0.845  0.086  1.0
  Ba  Ba5  1  0.169  0.655  0.588  1.0
  Ba  Ba6  1  0.252  0.204  0.925  1.0
  Ba  Ba7  1  0.702  0.319  0.411  1.0
  Cu  Cu8  1  0.001  0.035  0.498  1.0
  Si  Si9  1  0.768  0.427  0.090  1.0
  Si  Si10  1  0.306  0.056  0.569  1.0
  Si  Si11  1  0.237  0.612  0.921  1.0
  Si  Si12  1  0.786  0.879  0.431  1.0
  Si  Si13  1  0.770  0.201  0.975  1.0
  Si  Si14  1  0.210  0.287  0.455  1.0
  Si  Si15  1  0.289  0.822  0.044  1.0
  Si  Si16  1  0.670  0.677  0.541  1.0
  Si  Si17  1  0.945  0.199  0.150  1.0
  Si  Si18  1  0.023  0.248  0.625  1.0
  Si  Si19  1  0.464  0.793  0.869  1.0
  Si  Si20  1  0.618  0.690  0.348  1.0
  Si  Si21  1  0.126  0.894  0.867  1.0
  Si  Si22  1  0.941  0.700  0.831  1.0
  Si  Si23  1  0.595  0.214  0.149  1.0
  Si  Si24  1  0.358  0.292  0.640  1.0
[/CIF]
.
The crystal structure described by Ba8CuSi16 is Magnesium tetraboride-derived structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one Cu(1), one Si(10), one Si(11), one Si(13), one Si(14), one Si(16), one Si(2), one Si(4), one Si(5), and one Si(8) atom. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one Si(12), one Si(15), one Si(3), one Si(6), one Si(7), one Si(9), and two equivalent Si(1) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one Cu(1), one Si(12), one Si(15), one Si(2), one Si(4), one Si(6), one Si(7), and one Si(9) atom. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to one Si(1), one Si(10), one Si(11), one Si(14), one Si(16), one Si(3), one Si(5), and one Si(8) atom. In the fifth Ba site, Ba(5) is bonded in a 10-coordinate geometry to one Si(1), one Si(11), one Si(12), one Si(13), one Si(14), one Si(15), one Si(5), one Si(9), and two equivalent Si(7) atoms. In the sixth Ba site, Ba(6) is bonded in a 8-coordinate geometry to one Cu(1), one Si(10), one Si(14), one Si(16), one Si(2), one Si(4), one Si(6), and two equivalent Si(8) atoms. In the seventh Ba site, Ba(7) is bonded in a 7-coordinate geometry to one Si(10), one Si(13), one Si(15), one Si(16), one Si(3), one Si(7), one Si(9), and two equivalent Si(5) atoms. In the eighth Ba site, Ba(8) is bonded in a 9-coordinate geometry to one Cu(1), one Si(10), one Si(12), one Si(15), one Si(16), one Si(8), one Si(9), and two equivalent Si(6) atoms. Cu(1) is bonded in a 8-coordinate geometry to one Ba(1), one Ba(3), one Ba(6), one Ba(8), one Si(10), one Si(2), one Si(4), and one Si(6) atom. There are sixteen inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Ba(4), one Ba(5), two equivalent Ba(2), one Si(15), one Si(5), and one Si(9) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Ba(1), one Ba(3), one Ba(6), one Cu(1), one Si(10), one Si(16), and one Si(6) atom. In the third Si site, Si(3) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(4), one Ba(7), one Si(11), one Si(13), one Si(14), and one Si(7) atom. In the fourth Si site, Si(4) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(6), one Cu(1), one Si(12), and one Si(8) atom. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Ba(1), one Ba(4), one Ba(5), two equivalent Ba(7), one Si(1), one Si(15), and one Si(9) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Ba(2), one Ba(3), one Ba(6), two equivalent Ba(8), one Cu(1), one Si(10), one Si(16), and one Si(2) atom. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Ba(2), one Ba(3), one Ba(7), two equivalent Ba(5), one Si(11), one Si(13), and one Si(3) atom. In the eighth Si site, Si(8) is bonded to one Ba(1), one Ba(4), one Ba(8), two equivalent Ba(6), one Si(12), and one Si(4) atom to form distorted SiBa5Si2 pentagonal bipyramids that share  a cornercorner with one Si(14)Ba4Si2 octahedra, corners with two equivalent Si(8)Ba5Si2 pentagonal bipyramids, and  a faceface with one Si(14)Ba4Si2 octahedra. The corner-sharing octahedral tilt angles are 54°. In the ninth Si site, Si(9) is bonded in a 8-coordinate geometry to one Ba(2), one Ba(3), one Ba(5), one Ba(7), one Ba(8), one Si(1), one Si(15), and one Si(5) atom. In the tenth Si site, Si(10) is bonded in a 9-coordinate geometry to one Ba(1), one Ba(4), one Ba(6), one Ba(7), one Ba(8), one Cu(1), one Si(16), one Si(2), and one Si(6) atom. In the eleventh Si site, Si(11) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(4), one Ba(5), one Si(13), one Si(3), and one Si(7) atom. In the twelfth Si site, Si(12) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), one Ba(5), one Ba(8), one Si(4), and one Si(8) atom. In the thirteenth Si site, Si(13) is bonded in a 7-coordinate geometry to one Ba(1), one Ba(5), one Ba(7), one Si(11), one Si(14), one Si(3), and one Si(7) atom. In the fourteenth Si site, Si(14) is bonded to one Ba(1), one Ba(4), one Ba(5), one Ba(6), one Si(13), and one Si(3) atom to form a mixture of distorted face and corner-sharing SiBa4Si2 octahedra. In the fifteenth Si site, Si(15) is bonded in a 8-coordinate geometry to one Ba(2), one Ba(3), one Ba(5), one Ba(7), one Ba(8), one Si(1), one Si(5), and one Si(9) atom. In the sixteenth Si site, Si(16) is bonded in a 8-coordinate geometry to one Ba(1), one Ba(4), one Ba(6), one Ba(7), one Ba(8), one Si(10), one Si(2), and one Si(6) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba8CuSi16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.907
_cell_length_b   9.060
_cell_length_c   11.908
_cell_angle_alpha   89.638
_cell_angle_beta   89.644
_cell_angle_gamma   85.726
_symmetry_Int_Tables_number   1
_cell_volume   743.032
_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
  Ba  Ba0  1  0.731  0.989  0.717  1.0
  Ba  Ba1  1  0.272  0.504  0.194  1.0
  Ba  Ba2  1  0.312  0.990  0.289  1.0
  Ba  Ba3  1  0.666  0.468  0.789  1.0
  Ba  Ba4  1  0.790  0.845  0.086  1.0
  Ba  Ba5  1  0.169  0.655  0.588  1.0
  Ba  Ba6  1  0.252  0.204  0.925  1.0
  Ba  Ba7  1  0.702  0.319  0.411  1.0
  Cu  Cu8  1  0.001  0.035  0.498  1.0
  Si  Si9  1  0.768  0.427  0.090  1.0
  Si  Si10  1  0.306  0.056  0.569  1.0
  Si  Si11  1  0.237  0.612  0.921  1.0
  Si  Si12  1  0.786  0.879  0.431  1.0
  Si  Si13  1  0.770  0.201  0.975  1.0
  Si  Si14  1  0.210  0.287  0.455  1.0
  Si  Si15  1  0.289  0.822  0.044  1.0
  Si  Si16  1  0.670  0.677  0.541  1.0
  Si  Si17  1  0.945  0.199  0.150  1.0
  Si  Si18  1  0.023  0.248  0.625  1.0
  Si  Si19  1  0.464  0.793  0.869  1.0
  Si  Si20  1  0.618  0.690  0.348  1.0
  Si  Si21  1  0.126  0.894  0.867  1.0
  Si  Si22  1  0.941  0.700  0.831  1.0
  Si  Si23  1  0.595  0.214  0.149  1.0
  Si  Si24  1  0.358  0.292  0.640  1.0
[/CIF]
.