The structure described by Li2CoP2O7 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), and two equivalent O(1) atoms to form distorted LiO4 trigonal pyramids that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Li(2)O5 trigonal bipyramid, corners with two equivalent Li(1)O4 trigonal pyramids, and edges with two equivalent Co(1)O5 square pyramids. In the second Li site, Li(2) is bonded to one O(4), one O(6), one O(7), and two equivalent O(5) atoms to form distorted LiO5 trigonal bipyramids that share corners with three equivalent Co(1)O5 square pyramids, corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Li(2)O5 trigonal bipyramids, and  a cornercorner with one Li(1)O4 trigonal pyramid. Co(1) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form distorted CoO5 square pyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with three equivalent Li(2)O5 trigonal bipyramids, and edges with two equivalent Li(1)O4 trigonal pyramids. 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 corners with two equivalent Co(1)O5 square pyramids,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(2)O5 trigonal bipyramids, and corners with three equivalent Li(1)O4 trigonal pyramids. In the second P site, P(2) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(2)O5 trigonal bipyramids, and  a cornercorner with one Li(1)O4 trigonal pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to two equivalent Li(1), one Co(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Co(1), and one P(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Co(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Li(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(2) atom. is represented by the CIF file [CIF]
data_Li2CoP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.119
_cell_length_b   8.111
_cell_length_c   14.170
_cell_angle_alpha   67.751
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   544.601
_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  0.183  0.976  0.678  1.0
  Li  Li1  1  0.317  0.976  0.178  1.0
  Li  Li2  1  0.719  0.425  0.838  1.0
  Li  Li3  1  0.219  0.575  0.662  1.0
  Li  Li4  1  0.781  0.425  0.338  1.0
  Li  Li5  1  0.281  0.575  0.162  1.0
  Li  Li6  1  0.683  0.024  0.822  1.0
  Li  Li7  1  0.817  0.024  0.322  1.0
  Co  Co8  1  0.287  0.723  0.878  1.0
  Co  Co9  1  0.213  0.723  0.378  1.0
  Co  Co10  1  0.787  0.277  0.622  1.0
  Co  Co11  1  0.713  0.277  0.122  1.0
  P  P12  1  0.707  0.812  0.692  1.0
  P  P13  1  0.711  0.699  0.521  1.0
  P  P14  1  0.793  0.812  0.192  1.0
  P  P15  1  0.211  0.301  0.979  1.0
  P  P16  1  0.789  0.699  0.021  1.0
  P  P17  1  0.207  0.188  0.808  1.0
  P  P18  1  0.289  0.301  0.479  1.0
  P  P19  1  0.293  0.188  0.308  1.0
  O  O20  1  0.271  0.003  0.806  1.0
  O  O21  1  0.229  0.003  0.306  1.0
  O  O22  1  0.656  0.784  0.918  1.0
  O  O23  1  0.752  0.846  0.573  1.0
  O  O24  1  0.417  0.763  0.716  1.0
  O  O25  1  0.896  0.670  0.757  1.0
  O  O26  1  0.415  0.676  0.513  1.0
  O  O27  1  0.844  0.784  0.418  1.0
  O  O28  1  0.748  0.846  0.073  1.0
  O  O29  1  0.355  0.467  0.907  1.0
  O  O30  1  0.083  0.763  0.216  1.0
  O  O31  1  0.604  0.670  0.257  1.0
  O  O32  1  0.855  0.533  0.593  1.0
  O  O33  1  0.085  0.676  0.013  1.0
  O  O34  1  0.915  0.324  0.987  1.0
  O  O35  1  0.145  0.467  0.407  1.0
  O  O36  1  0.396  0.330  0.743  1.0
  O  O37  1  0.917  0.237  0.784  1.0
  O  O38  1  0.645  0.533  0.093  1.0
  O  O39  1  0.252  0.154  0.927  1.0
  O  O40  1  0.156  0.216  0.582  1.0
  O  O41  1  0.585  0.324  0.487  1.0
  O  O42  1  0.104  0.330  0.243  1.0
  O  O43  1  0.583  0.237  0.284  1.0
  O  O44  1  0.248  0.154  0.427  1.0
  O  O45  1  0.344  0.216  0.082  1.0
  O  O46  1  0.771  0.997  0.694  1.0
  O  O47  1  0.729  0.997  0.194  1.0
[/CIF]
.
The structure described by Li2CoP2O7 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), and two equivalent O(1) atoms to form distorted LiO4 trigonal pyramids that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Li(2)O5 trigonal bipyramid, corners with two equivalent Li(1)O4 trigonal pyramids, and edges with two equivalent Co(1)O5 square pyramids. In the second Li site, Li(2) is bonded to one O(4), one O(6), one O(7), and two equivalent O(5) atoms to form distorted LiO5 trigonal bipyramids that share corners with three equivalent Co(1)O5 square pyramids, corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Li(2)O5 trigonal bipyramids, and  a cornercorner with one Li(1)O4 trigonal pyramid. Co(1) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form distorted CoO5 square pyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with three equivalent Li(2)O5 trigonal bipyramids, and edges with two equivalent Li(1)O4 trigonal pyramids. 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 corners with two equivalent Co(1)O5 square pyramids,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(2)O5 trigonal bipyramids, and corners with three equivalent Li(1)O4 trigonal pyramids. In the second P site, P(2) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(2)O5 trigonal bipyramids, and  a cornercorner with one Li(1)O4 trigonal pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to two equivalent Li(1), one Co(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Co(1), and one P(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Co(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Li(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(2) atom. is represented by the CIF file [CIF]
data_Li2CoP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.119
_cell_length_b   8.111
_cell_length_c   14.170
_cell_angle_alpha   67.751
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   544.601
_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  0.183  0.976  0.678  1.0
  Li  Li1  1  0.317  0.976  0.178  1.0
  Li  Li2  1  0.719  0.425  0.838  1.0
  Li  Li3  1  0.219  0.575  0.662  1.0
  Li  Li4  1  0.781  0.425  0.338  1.0
  Li  Li5  1  0.281  0.575  0.162  1.0
  Li  Li6  1  0.683  0.024  0.822  1.0
  Li  Li7  1  0.817  0.024  0.322  1.0
  Co  Co8  1  0.287  0.723  0.878  1.0
  Co  Co9  1  0.213  0.723  0.378  1.0
  Co  Co10  1  0.787  0.277  0.622  1.0
  Co  Co11  1  0.713  0.277  0.122  1.0
  P  P12  1  0.707  0.812  0.692  1.0
  P  P13  1  0.711  0.699  0.521  1.0
  P  P14  1  0.793  0.812  0.192  1.0
  P  P15  1  0.211  0.301  0.979  1.0
  P  P16  1  0.789  0.699  0.021  1.0
  P  P17  1  0.207  0.188  0.808  1.0
  P  P18  1  0.289  0.301  0.479  1.0
  P  P19  1  0.293  0.188  0.308  1.0
  O  O20  1  0.271  0.003  0.806  1.0
  O  O21  1  0.229  0.003  0.306  1.0
  O  O22  1  0.656  0.784  0.918  1.0
  O  O23  1  0.752  0.846  0.573  1.0
  O  O24  1  0.417  0.763  0.716  1.0
  O  O25  1  0.896  0.670  0.757  1.0
  O  O26  1  0.415  0.676  0.513  1.0
  O  O27  1  0.844  0.784  0.418  1.0
  O  O28  1  0.748  0.846  0.073  1.0
  O  O29  1  0.355  0.467  0.907  1.0
  O  O30  1  0.083  0.763  0.216  1.0
  O  O31  1  0.604  0.670  0.257  1.0
  O  O32  1  0.855  0.533  0.593  1.0
  O  O33  1  0.085  0.676  0.013  1.0
  O  O34  1  0.915  0.324  0.987  1.0
  O  O35  1  0.145  0.467  0.407  1.0
  O  O36  1  0.396  0.330  0.743  1.0
  O  O37  1  0.917  0.237  0.784  1.0
  O  O38  1  0.645  0.533  0.093  1.0
  O  O39  1  0.252  0.154  0.927  1.0
  O  O40  1  0.156  0.216  0.582  1.0
  O  O41  1  0.585  0.324  0.487  1.0
  O  O42  1  0.104  0.330  0.243  1.0
  O  O43  1  0.583  0.237  0.284  1.0
  O  O44  1  0.248  0.154  0.427  1.0
  O  O45  1  0.344  0.216  0.082  1.0
  O  O46  1  0.771  0.997  0.694  1.0
  O  O47  1  0.729  0.997  0.194  1.0
[/CIF]
.