The crystal structure described by Li2Cu4Si4O13 is Chalcostibite-derived structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, and  a cornercorner with one Cu(3)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(10), one O(11), one O(12), and one O(9) atom. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(4), one O(5), and two equivalent O(1) atoms. In the second Cu site, Cu(2) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), and two equivalent O(6) atoms. In the third Cu site, Cu(3) is bonded to one O(10), one O(3), one O(7), and two equivalent O(8) atoms to form distorted CuO5 trigonal bipyramids that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  an edgeedge with one Cu(3)O5 trigonal bipyramid. In the fourth Cu site, Cu(4) is bonded in a 4-coordinate geometry to one O(10), one O(4), one O(7), and one O(9) atom. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(9) atom to form SiO4 tetrahedra that share corners with three equivalent Li(1)O4 tetrahedra and  a cornercorner with one Cu(3)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(13), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cu(3)O5 trigonal bipyramid. In the third Si site, Si(3) is bonded to one O(11), one O(12), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Cu(3)O5 trigonal bipyramids. In the fourth Si site, Si(4) is bonded to one O(1), one O(11), one O(13), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Cu(3)O5 trigonal bipyramid. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cu(1) and one Si(4) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Li(1), one Cu(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Li(1), one Cu(2), one Cu(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Li(1), one Cu(1), one Cu(4), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Cu(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Cu(2) and one Si(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Cu(3), one Cu(4), and one Si(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Cu(3) and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(2), one Cu(4), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Li(2), one Cu(3), one Cu(4), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(3), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Li(2), one Si(2), and one Si(3) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF file [CIF]
data_Li2Cu4Si4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.111
_cell_length_b   7.648
_cell_length_c   10.098
_cell_angle_alpha   70.605
_cell_angle_beta   87.370
_cell_angle_gamma   84.758
_symmetry_Int_Tables_number   1
_cell_volume   515.773
_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
  Li  Li0  1  0.205  0.614  0.886  1.0
  Li  Li1  1  0.761  0.434  0.574  1.0
  Li  Li2  1  0.239  0.566  0.426  1.0
  Li  Li3  1  0.795  0.386  0.114  1.0
  Cu  Cu4  1  0.908  0.824  0.001  1.0
  Cu  Cu5  1  0.440  0.807  0.985  1.0
  Cu  Cu6  1  0.412  0.822  0.618  1.0
  Cu  Cu7  1  0.952  0.784  0.639  1.0
  Cu  Cu8  1  0.048  0.216  0.361  1.0
  Cu  Cu9  1  0.588  0.178  0.382  1.0
  Cu  Cu10  1  0.560  0.193  0.015  1.0
  Cu  Cu11  1  0.092  0.176  0.999  1.0
  Si  Si12  1  0.716  0.589  0.829  1.0
  Si  Si13  1  0.289  0.404  0.711  1.0
  Si  Si14  1  0.612  0.117  0.721  1.0
  Si  Si15  1  0.052  0.100  0.715  1.0
  Si  Si16  1  0.948  0.900  0.285  1.0
  Si  Si17  1  0.388  0.883  0.279  1.0
  Si  Si18  1  0.711  0.596  0.289  1.0
  Si  Si19  1  0.284  0.411  0.171  1.0
  O  O20  1  0.090  0.008  0.883  1.0
  O  O21  1  0.741  0.372  0.932  1.0
  O  O22  1  0.500  0.689  0.836  1.0
  O  O23  1  0.894  0.705  0.855  1.0
  O  O24  1  0.246  0.362  0.876  1.0
  O  O25  1  0.584  0.019  0.890  1.0
  O  O26  1  0.121  0.963  0.627  1.0
  O  O27  1  0.564  0.015  0.612  1.0
  O  O28  1  0.767  0.615  0.663  1.0
  O  O29  1  0.259  0.623  0.615  1.0
  O  O30  1  0.829  0.171  0.687  1.0
  O  O31  1  0.504  0.328  0.676  1.0
  O  O32  1  0.147  0.299  0.645  1.0
  O  O33  1  0.853  0.701  0.355  1.0
  O  O34  1  0.496  0.672  0.324  1.0
  O  O35  1  0.171  0.829  0.313  1.0
  O  O36  1  0.741  0.377  0.385  1.0
  O  O37  1  0.233  0.385  0.337  1.0
  O  O38  1  0.436  0.985  0.388  1.0
  O  O39  1  0.879  0.037  0.373  1.0
  O  O40  1  0.416  0.981  0.110  1.0
  O  O41  1  0.754  0.638  0.124  1.0
  O  O42  1  0.106  0.295  0.145  1.0
  O  O43  1  0.500  0.311  0.164  1.0
  O  O44  1  0.259  0.628  0.068  1.0
  O  O45  1  0.910  0.992  0.117  1.0
[/CIF]
.
The crystal structure described by Li2Cu4Si4O13 is Chalcostibite-derived structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, and  a cornercorner with one Cu(3)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(10), one O(11), one O(12), and one O(9) atom. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(4), one O(5), and two equivalent O(1) atoms. In the second Cu site, Cu(2) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), and two equivalent O(6) atoms. In the third Cu site, Cu(3) is bonded to one O(10), one O(3), one O(7), and two equivalent O(8) atoms to form distorted CuO5 trigonal bipyramids that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  an edgeedge with one Cu(3)O5 trigonal bipyramid. In the fourth Cu site, Cu(4) is bonded in a 4-coordinate geometry to one O(10), one O(4), one O(7), and one O(9) atom. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(9) atom to form SiO4 tetrahedra that share corners with three equivalent Li(1)O4 tetrahedra and  a cornercorner with one Cu(3)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(13), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Cu(3)O5 trigonal bipyramid. In the third Si site, Si(3) is bonded to one O(11), one O(12), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Cu(3)O5 trigonal bipyramids. In the fourth Si site, Si(4) is bonded to one O(1), one O(11), one O(13), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Cu(3)O5 trigonal bipyramid. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cu(1) and one Si(4) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Li(1), one Cu(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Li(1), one Cu(2), one Cu(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Li(1), one Cu(1), one Cu(4), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Cu(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Cu(2) and one Si(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Cu(3), one Cu(4), and one Si(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Cu(3) and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(2), one Cu(4), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Li(2), one Cu(3), one Cu(4), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(3), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Li(2), one Si(2), and one Si(3) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF file [CIF]
data_Li2Cu4Si4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.111
_cell_length_b   7.648
_cell_length_c   10.098
_cell_angle_alpha   70.605
_cell_angle_beta   87.370
_cell_angle_gamma   84.758
_symmetry_Int_Tables_number   1
_cell_volume   515.773
_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
  Li  Li0  1  0.205  0.614  0.886  1.0
  Li  Li1  1  0.761  0.434  0.574  1.0
  Li  Li2  1  0.239  0.566  0.426  1.0
  Li  Li3  1  0.795  0.386  0.114  1.0
  Cu  Cu4  1  0.908  0.824  0.001  1.0
  Cu  Cu5  1  0.440  0.807  0.985  1.0
  Cu  Cu6  1  0.412  0.822  0.618  1.0
  Cu  Cu7  1  0.952  0.784  0.639  1.0
  Cu  Cu8  1  0.048  0.216  0.361  1.0
  Cu  Cu9  1  0.588  0.178  0.382  1.0
  Cu  Cu10  1  0.560  0.193  0.015  1.0
  Cu  Cu11  1  0.092  0.176  0.999  1.0
  Si  Si12  1  0.716  0.589  0.829  1.0
  Si  Si13  1  0.289  0.404  0.711  1.0
  Si  Si14  1  0.612  0.117  0.721  1.0
  Si  Si15  1  0.052  0.100  0.715  1.0
  Si  Si16  1  0.948  0.900  0.285  1.0
  Si  Si17  1  0.388  0.883  0.279  1.0
  Si  Si18  1  0.711  0.596  0.289  1.0
  Si  Si19  1  0.284  0.411  0.171  1.0
  O  O20  1  0.090  0.008  0.883  1.0
  O  O21  1  0.741  0.372  0.932  1.0
  O  O22  1  0.500  0.689  0.836  1.0
  O  O23  1  0.894  0.705  0.855  1.0
  O  O24  1  0.246  0.362  0.876  1.0
  O  O25  1  0.584  0.019  0.890  1.0
  O  O26  1  0.121  0.963  0.627  1.0
  O  O27  1  0.564  0.015  0.612  1.0
  O  O28  1  0.767  0.615  0.663  1.0
  O  O29  1  0.259  0.623  0.615  1.0
  O  O30  1  0.829  0.171  0.687  1.0
  O  O31  1  0.504  0.328  0.676  1.0
  O  O32  1  0.147  0.299  0.645  1.0
  O  O33  1  0.853  0.701  0.355  1.0
  O  O34  1  0.496  0.672  0.324  1.0
  O  O35  1  0.171  0.829  0.313  1.0
  O  O36  1  0.741  0.377  0.385  1.0
  O  O37  1  0.233  0.385  0.337  1.0
  O  O38  1  0.436  0.985  0.388  1.0
  O  O39  1  0.879  0.037  0.373  1.0
  O  O40  1  0.416  0.981  0.110  1.0
  O  O41  1  0.754  0.638  0.124  1.0
  O  O42  1  0.106  0.295  0.145  1.0
  O  O43  1  0.500  0.311  0.164  1.0
  O  O44  1  0.259  0.628  0.068  1.0
  O  O45  1  0.910  0.992  0.117  1.0
[/CIF]
.