The structure described by Li2Cu5(Si2O7)2 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(3), and two equivalent O(7) atoms. In the second Cu site, Cu(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(6) atoms. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Li(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Cu(1), and one Si(1) atom to form OLi2CuSi trigonal pyramids that share  a cornercorner with one O(3)LiCu2Si tetrahedra,  a cornercorner with one O(4)LiCu2Si trigonal pyramid,  an edgeedge with one O(3)LiCu2Si tetrahedra,  an edgeedge with one O(1)Li2CuSi trigonal pyramid, and  an edgeedge with one O(4)LiCu2Si trigonal pyramid. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cu(2), one Cu(3), and one Si(2) atom. In the third O site, O(3) is bonded to one Li(1), one Cu(1), one Cu(2), and one Si(2) atom to form OLiCu2Si tetrahedra that share  a cornercorner with one O(1)Li2CuSi trigonal pyramid, corners with two equivalent O(4)LiCu2Si trigonal pyramids, and  an edgeedge with one O(1)Li2CuSi trigonal pyramid. In the fourth O site, O(4) is bonded to one Li(1), one Cu(2), one Cu(3), and one Si(1) atom to form distorted OLiCu2Si trigonal pyramids that share corners with two equivalent O(3)LiCu2Si tetrahedra,  a cornercorner with one O(1)Li2CuSi trigonal pyramid,  a cornercorner with one O(4)LiCu2Si trigonal pyramid, and  an edgeedge with one O(1)Li2CuSi trigonal pyramid. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to two equivalent Cu(2) and one Si(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Cu(1) and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Cu5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.541
_cell_length_b   7.550
_cell_length_c   7.876
_cell_angle_alpha   115.115
_cell_angle_beta   89.862
_cell_angle_gamma   106.751
_symmetry_Int_Tables_number   1
_cell_volume   282.885
_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
  Li  Li0  1  0.762  0.888  0.551  1.0
  Li  Li1  1  0.238  0.112  0.449  1.0
  Cu  Cu2  1  0.079  0.388  0.815  1.0
  Cu  Cu3  1  0.921  0.612  0.185  1.0
  Cu  Cu4  1  0.329  0.428  0.286  1.0
  Cu  Cu5  1  0.671  0.572  0.714  1.0
  Cu  Cu6  1  0.000  1.000  0.000  1.0
  Si  Si7  1  0.802  0.214  0.403  1.0
  Si  Si8  1  0.495  0.228  0.860  1.0
  Si  Si9  1  0.505  0.772  0.140  1.0
  Si  Si10  1  0.198  0.786  0.597  1.0
  O  O11  1  0.101  0.825  0.423  1.0
  O  O12  1  0.696  0.774  0.980  1.0
  O  O13  1  0.409  0.337  0.735  1.0
  O  O14  1  0.968  0.812  0.734  1.0
  O  O15  1  0.461  0.985  0.716  1.0
  O  O16  1  0.591  0.663  0.265  1.0
  O  O17  1  0.290  0.586  0.544  1.0
  O  O18  1  0.710  0.414  0.456  1.0
  O  O19  1  0.032  0.188  0.266  1.0
  O  O20  1  0.303  0.226  0.020  1.0
  O  O21  1  0.790  0.350  0.961  1.0
  O  O22  1  0.899  0.175  0.577  1.0
  O  O23  1  0.210  0.650  0.039  1.0
  O  O24  1  0.539  0.015  0.284  1.0
[/CIF]
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The structure described by Li2Cu5(Si2O7)2 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(3), and two equivalent O(7) atoms. In the second Cu site, Cu(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(6) atoms. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Li(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Cu(1), and one Si(1) atom to form OLi2CuSi trigonal pyramids that share  a cornercorner with one O(3)LiCu2Si tetrahedra,  a cornercorner with one O(4)LiCu2Si trigonal pyramid,  an edgeedge with one O(3)LiCu2Si tetrahedra,  an edgeedge with one O(1)Li2CuSi trigonal pyramid, and  an edgeedge with one O(4)LiCu2Si trigonal pyramid. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cu(2), one Cu(3), and one Si(2) atom. In the third O site, O(3) is bonded to one Li(1), one Cu(1), one Cu(2), and one Si(2) atom to form OLiCu2Si tetrahedra that share  a cornercorner with one O(1)Li2CuSi trigonal pyramid, corners with two equivalent O(4)LiCu2Si trigonal pyramids, and  an edgeedge with one O(1)Li2CuSi trigonal pyramid. In the fourth O site, O(4) is bonded to one Li(1), one Cu(2), one Cu(3), and one Si(1) atom to form distorted OLiCu2Si trigonal pyramids that share corners with two equivalent O(3)LiCu2Si tetrahedra,  a cornercorner with one O(1)Li2CuSi trigonal pyramid,  a cornercorner with one O(4)LiCu2Si trigonal pyramid, and  an edgeedge with one O(1)Li2CuSi trigonal pyramid. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to two equivalent Cu(2) and one Si(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Cu(1) and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Cu5(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.541
_cell_length_b   7.550
_cell_length_c   7.876
_cell_angle_alpha   115.115
_cell_angle_beta   89.862
_cell_angle_gamma   106.751
_symmetry_Int_Tables_number   1
_cell_volume   282.885
_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
  Li  Li0  1  0.762  0.888  0.551  1.0
  Li  Li1  1  0.238  0.112  0.449  1.0
  Cu  Cu2  1  0.079  0.388  0.815  1.0
  Cu  Cu3  1  0.921  0.612  0.185  1.0
  Cu  Cu4  1  0.329  0.428  0.286  1.0
  Cu  Cu5  1  0.671  0.572  0.714  1.0
  Cu  Cu6  1  0.000  1.000  0.000  1.0
  Si  Si7  1  0.802  0.214  0.403  1.0
  Si  Si8  1  0.495  0.228  0.860  1.0
  Si  Si9  1  0.505  0.772  0.140  1.0
  Si  Si10  1  0.198  0.786  0.597  1.0
  O  O11  1  0.101  0.825  0.423  1.0
  O  O12  1  0.696  0.774  0.980  1.0
  O  O13  1  0.409  0.337  0.735  1.0
  O  O14  1  0.968  0.812  0.734  1.0
  O  O15  1  0.461  0.985  0.716  1.0
  O  O16  1  0.591  0.663  0.265  1.0
  O  O17  1  0.290  0.586  0.544  1.0
  O  O18  1  0.710  0.414  0.456  1.0
  O  O19  1  0.032  0.188  0.266  1.0
  O  O20  1  0.303  0.226  0.020  1.0
  O  O21  1  0.790  0.350  0.961  1.0
  O  O22  1  0.899  0.175  0.577  1.0
  O  O23  1  0.210  0.650  0.039  1.0
  O  O24  1  0.539  0.015  0.284  1.0
[/CIF]
.