The crystal structure described by Li2CuP2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, corners with three equivalent Cu(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. Cu(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and corners with three equivalent Cu(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids, and corners with three equivalent Li(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one Cu(1), and one P(2) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Li(2), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Cu(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Cu(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Cu(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. is represented by the CIF card [CIF]
data_Li2CuP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.319
_cell_length_b   5.013
_cell_length_c   9.208
_cell_angle_alpha   61.190
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   538.662
_cell_formula_units_Z   4
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  0.112  0.952  0.865  1.0
  Li  Li1  1  0.888  0.048  0.135  1.0
  Li  Li2  1  0.296  0.569  0.173  1.0
  Li  Li3  1  0.796  0.431  0.327  1.0
  Li  Li4  1  0.388  0.952  0.365  1.0
  Li  Li5  1  0.704  0.431  0.827  1.0
  Li  Li6  1  0.204  0.569  0.673  1.0
  Li  Li7  1  0.612  0.048  0.635  1.0
  Cu  Cu8  1  0.149  0.950  0.255  1.0
  Cu  Cu9  1  0.649  0.050  0.245  1.0
  Cu  Cu10  1  0.351  0.950  0.755  1.0
  Cu  Cu11  1  0.851  0.050  0.745  1.0
  P  P12  1  0.830  0.746  0.528  1.0
  P  P13  1  0.170  0.254  0.472  1.0
  P  P14  1  0.525  0.516  0.278  1.0
  P  P15  1  0.025  0.484  0.222  1.0
  P  P16  1  0.330  0.254  0.972  1.0
  P  P17  1  0.975  0.516  0.778  1.0
  P  P18  1  0.670  0.746  0.028  1.0
  P  P19  1  0.475  0.484  0.722  1.0
  O  O20  1  0.947  0.690  0.580  1.0
  O  O21  1  0.108  0.731  0.135  1.0
  O  O22  1  0.553  0.690  0.080  1.0
  O  O23  1  0.709  0.441  0.046  1.0
  O  O24  1  0.291  0.559  0.954  1.0
  O  O25  1  0.447  0.310  0.920  1.0
  O  O26  1  0.892  0.269  0.865  1.0
  O  O27  1  0.279  0.183  0.843  1.0
  O  O28  1  0.678  0.010  0.853  1.0
  O  O29  1  0.968  0.766  0.831  1.0
  O  O30  1  0.079  0.385  0.791  1.0
  O  O31  1  0.579  0.615  0.709  1.0
  O  O32  1  0.468  0.234  0.669  1.0
  O  O33  1  0.322  0.990  0.147  1.0
  O  O34  1  0.178  0.990  0.647  1.0
  O  O35  1  0.392  0.731  0.635  1.0
  O  O36  1  0.779  0.817  0.657  1.0
  O  O37  1  0.791  0.441  0.546  1.0
  O  O38  1  0.209  0.559  0.454  1.0
  O  O39  1  0.053  0.310  0.420  1.0
  O  O40  1  0.608  0.269  0.365  1.0
  O  O41  1  0.822  0.010  0.353  1.0
  O  O42  1  0.221  0.183  0.343  1.0
  O  O43  1  0.532  0.766  0.331  1.0
  O  O44  1  0.421  0.385  0.291  1.0
  O  O45  1  0.921  0.615  0.209  1.0
  O  O46  1  0.032  0.234  0.169  1.0
  O  O47  1  0.721  0.817  0.157  1.0
[/CIF]
.
The crystal structure described by Li2CuP2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, corners with three equivalent Cu(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. Cu(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and corners with three equivalent Cu(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids, and corners with three equivalent Li(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one Cu(1), and one P(2) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Li(2), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Cu(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Cu(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Cu(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. is represented by the CIF card [CIF]
data_Li2CuP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.319
_cell_length_b   5.013
_cell_length_c   9.208
_cell_angle_alpha   61.190
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   538.662
_cell_formula_units_Z   4
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  0.112  0.952  0.865  1.0
  Li  Li1  1  0.888  0.048  0.135  1.0
  Li  Li2  1  0.296  0.569  0.173  1.0
  Li  Li3  1  0.796  0.431  0.327  1.0
  Li  Li4  1  0.388  0.952  0.365  1.0
  Li  Li5  1  0.704  0.431  0.827  1.0
  Li  Li6  1  0.204  0.569  0.673  1.0
  Li  Li7  1  0.612  0.048  0.635  1.0
  Cu  Cu8  1  0.149  0.950  0.255  1.0
  Cu  Cu9  1  0.649  0.050  0.245  1.0
  Cu  Cu10  1  0.351  0.950  0.755  1.0
  Cu  Cu11  1  0.851  0.050  0.745  1.0
  P  P12  1  0.830  0.746  0.528  1.0
  P  P13  1  0.170  0.254  0.472  1.0
  P  P14  1  0.525  0.516  0.278  1.0
  P  P15  1  0.025  0.484  0.222  1.0
  P  P16  1  0.330  0.254  0.972  1.0
  P  P17  1  0.975  0.516  0.778  1.0
  P  P18  1  0.670  0.746  0.028  1.0
  P  P19  1  0.475  0.484  0.722  1.0
  O  O20  1  0.947  0.690  0.580  1.0
  O  O21  1  0.108  0.731  0.135  1.0
  O  O22  1  0.553  0.690  0.080  1.0
  O  O23  1  0.709  0.441  0.046  1.0
  O  O24  1  0.291  0.559  0.954  1.0
  O  O25  1  0.447  0.310  0.920  1.0
  O  O26  1  0.892  0.269  0.865  1.0
  O  O27  1  0.279  0.183  0.843  1.0
  O  O28  1  0.678  0.010  0.853  1.0
  O  O29  1  0.968  0.766  0.831  1.0
  O  O30  1  0.079  0.385  0.791  1.0
  O  O31  1  0.579  0.615  0.709  1.0
  O  O32  1  0.468  0.234  0.669  1.0
  O  O33  1  0.322  0.990  0.147  1.0
  O  O34  1  0.178  0.990  0.647  1.0
  O  O35  1  0.392  0.731  0.635  1.0
  O  O36  1  0.779  0.817  0.657  1.0
  O  O37  1  0.791  0.441  0.546  1.0
  O  O38  1  0.209  0.559  0.454  1.0
  O  O39  1  0.053  0.310  0.420  1.0
  O  O40  1  0.608  0.269  0.365  1.0
  O  O41  1  0.822  0.010  0.353  1.0
  O  O42  1  0.221  0.183  0.343  1.0
  O  O43  1  0.532  0.766  0.331  1.0
  O  O44  1  0.421  0.385  0.291  1.0
  O  O45  1  0.921  0.615  0.209  1.0
  O  O46  1  0.032  0.234  0.169  1.0
  O  O47  1  0.721  0.817  0.157  1.0
[/CIF]
.