The structure described by Li7Cu(SiO4)2 crystallizes in the monoclinic C2/m space group. There are six inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(2), one O(5), and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with four equivalent Li(1)O4 tetrahedra. In the third Li site, Li(3) is bonded to one O(1), one O(4), and two equivalent O(6) atoms to form LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(6) atom. In the fifth Li site, Li(5) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(5) atoms. In the sixth Li site, Li(6) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. Cu(1) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(6) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, and corners with four equivalent Li(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Li(3), one Li(6), two equivalent Li(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi4Si trigonal bipyramids. In the second O site, O(2) is bonded to one Li(2), one Li(5), two equivalent Li(1), and one Si(2) atom to form a mixture of edge and corner-sharing OLi4Si trigonal bipyramids. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Li(1), one Li(2), one Li(4), one Cu(1), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Li(3), one Li(6), two equivalent Li(4), and one Si(1) atom to form a mixture of edge and corner-sharing OLi4Si trigonal bipyramids. In the fifth O site, O(5) is bonded to one Li(2), one Li(5), two equivalent Li(4), and one Si(2) atom to form a mixture of distorted edge and corner-sharing OLi4Si trigonal bipyramids. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Li(1), one Li(3), one Li(4), one Cu(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Li7Cu(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.377
_cell_length_b   8.377
_cell_length_c   7.812
_cell_angle_alpha   89.391
_cell_angle_beta   89.391
_cell_angle_gamma   44.527
_symmetry_Int_Tables_number   1
_cell_volume   384.356
_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  0.342  0.827  0.626  1.0
  Li  Li1  1  0.827  0.342  0.626  1.0
  Li  Li2  1  0.073  0.073  0.296  1.0
  Li  Li3  1  0.648  0.648  0.853  1.0
  Li  Li4  1  0.939  0.430  0.158  1.0
  Li  Li5  1  0.430  0.939  0.158  1.0
  Li  Li6  1  0.061  0.570  0.842  1.0
  Li  Li7  1  0.570  0.061  0.842  1.0
  Li  Li8  1  0.352  0.352  0.147  1.0
  Li  Li9  1  0.927  0.927  0.704  1.0
  Li  Li10  1  0.658  0.173  0.374  1.0
  Li  Li11  1  0.173  0.658  0.374  1.0
  Li  Li12  1  0.000  0.000  0.000  1.0
  Li  Li13  1  0.500  0.500  0.000  1.0
  Cu  Cu14  1  0.268  0.268  0.598  1.0
  Cu  Cu15  1  0.732  0.732  0.402  1.0
  Si  Si16  1  0.573  0.573  0.288  1.0
  Si  Si17  1  0.145  0.145  0.851  1.0
  Si  Si18  1  0.855  0.855  0.149  1.0
  Si  Si19  1  0.427  0.427  0.712  1.0
  O  O20  1  0.532  0.532  0.737  1.0
  O  O21  1  0.048  0.048  0.763  1.0
  O  O22  1  0.395  0.824  0.385  1.0
  O  O23  1  0.824  0.395  0.385  1.0
  O  O24  1  0.616  0.616  0.092  1.0
  O  O25  1  0.132  0.132  0.060  1.0
  O  O26  1  0.410  0.981  0.780  1.0
  O  O27  1  0.981  0.410  0.780  1.0
  O  O28  1  0.019  0.590  0.220  1.0
  O  O29  1  0.590  0.019  0.220  1.0
  O  O30  1  0.868  0.868  0.940  1.0
  O  O31  1  0.384  0.384  0.908  1.0
  O  O32  1  0.605  0.176  0.615  1.0
  O  O33  1  0.176  0.605  0.615  1.0
  O  O34  1  0.952  0.952  0.237  1.0
  O  O35  1  0.468  0.468  0.263  1.0
[/CIF]
.
The structure described by Li7Cu(SiO4)2 crystallizes in the monoclinic C2/m space group. There are six inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(2), one O(5), and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with four equivalent Li(1)O4 tetrahedra. In the third Li site, Li(3) is bonded to one O(1), one O(4), and two equivalent O(6) atoms to form LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(6) atom. In the fifth Li site, Li(5) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(5) atoms. In the sixth Li site, Li(6) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. Cu(1) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(6) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, and corners with four equivalent Li(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Li(3), one Li(6), two equivalent Li(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi4Si trigonal bipyramids. In the second O site, O(2) is bonded to one Li(2), one Li(5), two equivalent Li(1), and one Si(2) atom to form a mixture of edge and corner-sharing OLi4Si trigonal bipyramids. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Li(1), one Li(2), one Li(4), one Cu(1), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Li(3), one Li(6), two equivalent Li(4), and one Si(1) atom to form a mixture of edge and corner-sharing OLi4Si trigonal bipyramids. In the fifth O site, O(5) is bonded to one Li(2), one Li(5), two equivalent Li(4), and one Si(2) atom to form a mixture of distorted edge and corner-sharing OLi4Si trigonal bipyramids. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Li(1), one Li(3), one Li(4), one Cu(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Li7Cu(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.377
_cell_length_b   8.377
_cell_length_c   7.812
_cell_angle_alpha   89.391
_cell_angle_beta   89.391
_cell_angle_gamma   44.527
_symmetry_Int_Tables_number   1
_cell_volume   384.356
_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  0.342  0.827  0.626  1.0
  Li  Li1  1  0.827  0.342  0.626  1.0
  Li  Li2  1  0.073  0.073  0.296  1.0
  Li  Li3  1  0.648  0.648  0.853  1.0
  Li  Li4  1  0.939  0.430  0.158  1.0
  Li  Li5  1  0.430  0.939  0.158  1.0
  Li  Li6  1  0.061  0.570  0.842  1.0
  Li  Li7  1  0.570  0.061  0.842  1.0
  Li  Li8  1  0.352  0.352  0.147  1.0
  Li  Li9  1  0.927  0.927  0.704  1.0
  Li  Li10  1  0.658  0.173  0.374  1.0
  Li  Li11  1  0.173  0.658  0.374  1.0
  Li  Li12  1  0.000  0.000  0.000  1.0
  Li  Li13  1  0.500  0.500  0.000  1.0
  Cu  Cu14  1  0.268  0.268  0.598  1.0
  Cu  Cu15  1  0.732  0.732  0.402  1.0
  Si  Si16  1  0.573  0.573  0.288  1.0
  Si  Si17  1  0.145  0.145  0.851  1.0
  Si  Si18  1  0.855  0.855  0.149  1.0
  Si  Si19  1  0.427  0.427  0.712  1.0
  O  O20  1  0.532  0.532  0.737  1.0
  O  O21  1  0.048  0.048  0.763  1.0
  O  O22  1  0.395  0.824  0.385  1.0
  O  O23  1  0.824  0.395  0.385  1.0
  O  O24  1  0.616  0.616  0.092  1.0
  O  O25  1  0.132  0.132  0.060  1.0
  O  O26  1  0.410  0.981  0.780  1.0
  O  O27  1  0.981  0.410  0.780  1.0
  O  O28  1  0.019  0.590  0.220  1.0
  O  O29  1  0.590  0.019  0.220  1.0
  O  O30  1  0.868  0.868  0.940  1.0
  O  O31  1  0.384  0.384  0.908  1.0
  O  O32  1  0.605  0.176  0.615  1.0
  O  O33  1  0.176  0.605  0.615  1.0
  O  O34  1  0.952  0.952  0.237  1.0
  O  O35  1  0.468  0.468  0.263  1.0
[/CIF]
.