The material described by Li2NiP2O7 crystallizes in the triclinic P1 space group. There are eight inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(12), one O(27), one O(3), one O(8), and one O(9) atom to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra,  an edgeedge with one Ni(3)O6 octahedra, and  a faceface with one Ni(2)O6 octahedra. In the second Li site, Li(2) is bonded to one O(10), one O(13), one O(14), and one O(7) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  an edgeedge with one Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles are 35°. In the third Li site, Li(3) is bonded in a distorted trigonal non-coplanar geometry to one O(14), one O(17), and one O(19) atom. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to one O(11), one O(2), one O(21), and one O(23) atom. In the fifth Li site, Li(5) is bonded in a 5-coordinate geometry to one O(12), one O(18), one O(5), one O(6), and one O(8) atom. In the sixth Li site, Li(6) is bonded in a 5-coordinate geometry to one O(17), one O(25), one O(26), one O(4), and one O(7) atom. In the seventh Li site, Li(7) is bonded in a distorted see-saw-like geometry to one O(10), one O(17), one O(28), and one O(7) atom. In the eighth Li site, Li(8) is bonded in a 3-coordinate geometry to one O(20), one O(23), and one O(4) atom. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(10), one O(11), one O(16), one O(20), one O(21), and one O(28) atom to form distorted NiO6 octahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  an edgeedge with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. In the second Ni site, Ni(2) is bonded to one O(12), one O(16), one O(25), one O(26), one O(27), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(8)O4 tetrahedra, and  a faceface with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 61°. In the third Ni site, Ni(3) is bonded to one O(15), one O(19), one O(24), one O(3), one O(6), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 61°. In the fourth Ni site, Ni(4) is bonded to one O(13), one O(15), one O(2), one O(23), one O(4), and one O(7) atom to form distorted NiO6 octahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  an edgeedge with one P(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 61°. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(24), one O(4), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-56°. In the second P site, P(2) is bonded to one O(15), one O(22), one O(26), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one P(8)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  an edgeedge with one Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. In the third P site, P(3) is bonded to one O(1), one O(10), one O(16), and one O(19) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. In the fourth P site, P(4) is bonded to one O(13), one O(18), one O(20), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, and  a cornercorner with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 43-57°. In the fifth P site, P(5) is bonded to one O(11), one O(12), one O(17), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one P(6)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 50-53°. In the sixth P site, P(6) is bonded to one O(2), one O(28), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(5)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 42-57°. In the seventh P site, P(7) is bonded to one O(14), one O(18), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, and  a cornercorner with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 51-56°. In the eighth P site, P(8) is bonded to one O(21), one O(22), one O(25), and one O(27) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 41-56°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(4), one Ni(4), and one P(6) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(3), and one P(7) atom. In the fourth O site, O(4) is bonded to one Li(6), one Li(8), one Ni(4), and one P(1) atom to form distorted corner-sharing OLi2NiP tetrahedra. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(5), one P(5), and one P(6) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(5), one Ni(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Li(2), one Li(6), one Li(7), one Ni(4), and one P(2) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(5), one Ni(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(3), and one P(6) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Li(2), one Li(7), one Ni(1), and one P(3) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Li(4), one Ni(1), and one P(5) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Li(1), one Li(5), one Ni(2), and one P(5) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Li(2), one Ni(4), and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Li(2), one Li(3), and one P(7) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ni(3), one Ni(4), and one P(2) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(2), and one P(3) atom. In the seventeenth O site, O(17) is bonded to one Li(3), one Li(6), one Li(7), and one P(5) atom to form distorted corner-sharing OLi3P trigonal pyramids. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Li(5), one P(4), and one P(7) atom. In the nineteenth O site, O(19) is bonded in a trigonal planar geometry to one Li(3), one Ni(3), and one P(3) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Li(8), one Ni(1), and one P(4) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Li(4), one Ni(1), and one P(8) atom. In the twenty-second O site, O(22) is bonded in a bent 120 degrees geometry to one P(2) and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted rectangular see-saw-like geometry to one Li(4), one Li(8), one Ni(4), and one P(7) atom. In the twenty-fourth O site, O(24) is bonded in a distorted bent 150 degrees geometry to one Ni(3) and one P(1) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Li(6), one Ni(2), and one P(8) atom. In the twenty-sixth O site, O(26) is bonded in a 3-coordinate geometry to one Li(6), one Ni(2), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a 3-coordinate geometry to one Li(1), one Ni(2), and one P(8) atom. In the twenty-eighth O site, O(28) is bonded in a trigonal planar geometry to one Li(7), one Ni(1), and one P(6) atom. is represented by the CIF file [CIF]
data_Li2NiP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.512
_cell_length_b   9.192
_cell_length_c   10.276
_cell_angle_alpha   113.585
_cell_angle_beta   87.192
_cell_angle_gamma   107.027
_symmetry_Int_Tables_number   1
_cell_volume   537.393
_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  0.580  0.500  0.968  1.0
  Li  Li1  1  0.346  0.930  0.382  1.0
  Li  Li2  1  0.930  0.832  0.509  1.0
  Li  Li3  1  0.873  0.892  0.910  1.0
  Li  Li4  1  0.159  0.488  0.039  1.0
  Li  Li5  1  0.048  0.232  0.518  1.0
  Li  Li6  1  0.647  0.072  0.620  1.0
  Li  Li7  1  0.184  0.120  0.125  1.0
  Ni  Ni8  1  0.284  0.894  0.778  1.0
  Ni  Ni9  1  0.368  0.506  0.742  1.0
  Ni  Ni10  1  0.625  0.484  0.247  1.0
  Ni  Ni11  1  0.724  0.095  0.220  1.0
  P  P12  1  0.112  0.438  0.295  1.0
  P  P13  1  0.567  0.295  0.462  1.0
  P  P14  1  0.429  0.703  0.531  1.0
  P  P15  1  0.315  0.805  0.051  1.0
  P  P16  1  0.084  0.182  0.797  1.0
  P  P17  1  0.692  0.185  0.947  1.0
  P  P18  1  0.919  0.804  0.196  1.0
  P  P19  1  0.878  0.546  0.698  1.0
  O  O20  1  0.225  0.544  0.455  1.0
  O  O21  1  0.739  0.081  0.019  1.0
  O  O22  1  0.709  0.665  0.169  1.0
  O  O23  1  0.023  0.261  0.292  1.0
  O  O24  1  0.927  0.280  0.906  1.0
  O  O25  1  0.291  0.446  0.192  1.0
  O  O26  1  0.632  0.145  0.461  1.0
  O  O27  1  0.391  0.657  0.957  1.0
  O  O28  1  0.603  0.325  0.038  1.0
  O  O29  1  0.371  0.858  0.541  1.0
  O  O30  1  0.109  0.059  0.857  1.0
  O  O31  1  0.289  0.326  0.822  1.0
  O  O32  1  0.446  0.912  0.195  1.0
  O  O33  1  0.028  0.890  0.347  1.0
  O  O34  1  0.549  0.275  0.306  1.0
  O  O35  1  0.443  0.711  0.685  1.0
  O  O36  1  0.971  0.094  0.646  1.0
  O  O37  1  0.083  0.708  0.091  1.0
  O  O38  1  0.627  0.678  0.450  1.0
  O  O39  1  0.273  0.913  0.981  1.0
  O  O40  1  0.978  0.730  0.724  1.0
  O  O41  1  0.765  0.459  0.536  1.0
  O  O42  1  0.904  0.929  0.135  1.0
  O  O43  1  0.947  0.514  0.274  1.0
  O  O44  1  0.039  0.453  0.696  1.0
  O  O45  1  0.367  0.319  0.541  1.0
  O  O46  1  0.693  0.525  0.794  1.0
  O  O47  1  0.565  0.076  0.803  1.0
[/CIF]
.
The material described by Li2NiP2O7 crystallizes in the triclinic P1 space group. There are eight inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(12), one O(27), one O(3), one O(8), and one O(9) atom to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra,  an edgeedge with one Ni(3)O6 octahedra, and  a faceface with one Ni(2)O6 octahedra. In the second Li site, Li(2) is bonded to one O(10), one O(13), one O(14), and one O(7) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  an edgeedge with one Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles are 35°. In the third Li site, Li(3) is bonded in a distorted trigonal non-coplanar geometry to one O(14), one O(17), and one O(19) atom. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to one O(11), one O(2), one O(21), and one O(23) atom. In the fifth Li site, Li(5) is bonded in a 5-coordinate geometry to one O(12), one O(18), one O(5), one O(6), and one O(8) atom. In the sixth Li site, Li(6) is bonded in a 5-coordinate geometry to one O(17), one O(25), one O(26), one O(4), and one O(7) atom. In the seventh Li site, Li(7) is bonded in a distorted see-saw-like geometry to one O(10), one O(17), one O(28), and one O(7) atom. In the eighth Li site, Li(8) is bonded in a 3-coordinate geometry to one O(20), one O(23), and one O(4) atom. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(10), one O(11), one O(16), one O(20), one O(21), and one O(28) atom to form distorted NiO6 octahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  an edgeedge with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. In the second Ni site, Ni(2) is bonded to one O(12), one O(16), one O(25), one O(26), one O(27), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(8)O4 tetrahedra, and  a faceface with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 61°. In the third Ni site, Ni(3) is bonded to one O(15), one O(19), one O(24), one O(3), one O(6), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 61°. In the fourth Ni site, Ni(4) is bonded to one O(13), one O(15), one O(2), one O(23), one O(4), and one O(7) atom to form distorted NiO6 octahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  an edgeedge with one P(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 61°. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(24), one O(4), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-56°. In the second P site, P(2) is bonded to one O(15), one O(22), one O(26), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one P(8)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  an edgeedge with one Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. In the third P site, P(3) is bonded to one O(1), one O(10), one O(16), and one O(19) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. In the fourth P site, P(4) is bonded to one O(13), one O(18), one O(20), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, and  a cornercorner with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 43-57°. In the fifth P site, P(5) is bonded to one O(11), one O(12), one O(17), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one P(6)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 50-53°. In the sixth P site, P(6) is bonded to one O(2), one O(28), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(5)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 42-57°. In the seventh P site, P(7) is bonded to one O(14), one O(18), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, and  a cornercorner with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 51-56°. In the eighth P site, P(8) is bonded to one O(21), one O(22), one O(25), and one O(27) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 41-56°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(4), one Ni(4), and one P(6) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(3), and one P(7) atom. In the fourth O site, O(4) is bonded to one Li(6), one Li(8), one Ni(4), and one P(1) atom to form distorted corner-sharing OLi2NiP tetrahedra. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(5), one P(5), and one P(6) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(5), one Ni(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Li(2), one Li(6), one Li(7), one Ni(4), and one P(2) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(5), one Ni(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(3), and one P(6) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Li(2), one Li(7), one Ni(1), and one P(3) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Li(4), one Ni(1), and one P(5) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Li(1), one Li(5), one Ni(2), and one P(5) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Li(2), one Ni(4), and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Li(2), one Li(3), and one P(7) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ni(3), one Ni(4), and one P(2) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(2), and one P(3) atom. In the seventeenth O site, O(17) is bonded to one Li(3), one Li(6), one Li(7), and one P(5) atom to form distorted corner-sharing OLi3P trigonal pyramids. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Li(5), one P(4), and one P(7) atom. In the nineteenth O site, O(19) is bonded in a trigonal planar geometry to one Li(3), one Ni(3), and one P(3) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Li(8), one Ni(1), and one P(4) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Li(4), one Ni(1), and one P(8) atom. In the twenty-second O site, O(22) is bonded in a bent 120 degrees geometry to one P(2) and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted rectangular see-saw-like geometry to one Li(4), one Li(8), one Ni(4), and one P(7) atom. In the twenty-fourth O site, O(24) is bonded in a distorted bent 150 degrees geometry to one Ni(3) and one P(1) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Li(6), one Ni(2), and one P(8) atom. In the twenty-sixth O site, O(26) is bonded in a 3-coordinate geometry to one Li(6), one Ni(2), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a 3-coordinate geometry to one Li(1), one Ni(2), and one P(8) atom. In the twenty-eighth O site, O(28) is bonded in a trigonal planar geometry to one Li(7), one Ni(1), and one P(6) atom. is represented by the CIF file [CIF]
data_Li2NiP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.512
_cell_length_b   9.192
_cell_length_c   10.276
_cell_angle_alpha   113.585
_cell_angle_beta   87.192
_cell_angle_gamma   107.027
_symmetry_Int_Tables_number   1
_cell_volume   537.393
_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  0.580  0.500  0.968  1.0
  Li  Li1  1  0.346  0.930  0.382  1.0
  Li  Li2  1  0.930  0.832  0.509  1.0
  Li  Li3  1  0.873  0.892  0.910  1.0
  Li  Li4  1  0.159  0.488  0.039  1.0
  Li  Li5  1  0.048  0.232  0.518  1.0
  Li  Li6  1  0.647  0.072  0.620  1.0
  Li  Li7  1  0.184  0.120  0.125  1.0
  Ni  Ni8  1  0.284  0.894  0.778  1.0
  Ni  Ni9  1  0.368  0.506  0.742  1.0
  Ni  Ni10  1  0.625  0.484  0.247  1.0
  Ni  Ni11  1  0.724  0.095  0.220  1.0
  P  P12  1  0.112  0.438  0.295  1.0
  P  P13  1  0.567  0.295  0.462  1.0
  P  P14  1  0.429  0.703  0.531  1.0
  P  P15  1  0.315  0.805  0.051  1.0
  P  P16  1  0.084  0.182  0.797  1.0
  P  P17  1  0.692  0.185  0.947  1.0
  P  P18  1  0.919  0.804  0.196  1.0
  P  P19  1  0.878  0.546  0.698  1.0
  O  O20  1  0.225  0.544  0.455  1.0
  O  O21  1  0.739  0.081  0.019  1.0
  O  O22  1  0.709  0.665  0.169  1.0
  O  O23  1  0.023  0.261  0.292  1.0
  O  O24  1  0.927  0.280  0.906  1.0
  O  O25  1  0.291  0.446  0.192  1.0
  O  O26  1  0.632  0.145  0.461  1.0
  O  O27  1  0.391  0.657  0.957  1.0
  O  O28  1  0.603  0.325  0.038  1.0
  O  O29  1  0.371  0.858  0.541  1.0
  O  O30  1  0.109  0.059  0.857  1.0
  O  O31  1  0.289  0.326  0.822  1.0
  O  O32  1  0.446  0.912  0.195  1.0
  O  O33  1  0.028  0.890  0.347  1.0
  O  O34  1  0.549  0.275  0.306  1.0
  O  O35  1  0.443  0.711  0.685  1.0
  O  O36  1  0.971  0.094  0.646  1.0
  O  O37  1  0.083  0.708  0.091  1.0
  O  O38  1  0.627  0.678  0.450  1.0
  O  O39  1  0.273  0.913  0.981  1.0
  O  O40  1  0.978  0.730  0.724  1.0
  O  O41  1  0.765  0.459  0.536  1.0
  O  O42  1  0.904  0.929  0.135  1.0
  O  O43  1  0.947  0.514  0.274  1.0
  O  O44  1  0.039  0.453  0.696  1.0
  O  O45  1  0.367  0.319  0.541  1.0
  O  O46  1  0.693  0.525  0.794  1.0
  O  O47  1  0.565  0.076  0.803  1.0
[/CIF]
.