The material described by Li2Nb(PO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(6) atoms. In the second Li site, Li(2) is bonded to one O(6), one O(7), one O(8), and two equivalent O(4) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, edges with two equivalent Nb(1)O6 octahedra, and  an edgeedge with one Li(2)O5 trigonal bipyramid. Nb(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form distorted NbO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and edges with two equivalent Li(2)O5 trigonal bipyramids. 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 three equivalent Nb(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Li(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 48-57°. In the second P site, P(2) is bonded to one O(3), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Li(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 40-52°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Li(2), one Nb(1), and one P(2) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Li(2), one Nb(1), and one P(2) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Li(1), one Nb(1), and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Li(1) and one Nb(1) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one P(1), and one P(2) atom. In the sixth O site, O(4) is bonded to two equivalent Li(2), one Nb(1), and one P(1) atom to form distorted edge-sharing OLi2NbP tetrahedra. In the seventh O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Nb(1) and one P(1) atom. In the eighth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), two equivalent Li(1), and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Nb(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.612
_cell_length_b   6.441
_cell_length_c   7.779
_cell_angle_alpha   81.127
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   624.392
_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  0.228  0.353  0.071  1.0
  Li  Li1  1  0.272  0.853  0.071  1.0
  Li  Li2  1  0.622  0.060  0.553  1.0
  Li  Li3  1  0.122  0.440  0.447  1.0
  Li  Li4  1  0.878  0.560  0.553  1.0
  Li  Li5  1  0.378  0.940  0.447  1.0
  Li  Li6  1  0.728  0.147  0.929  1.0
  Li  Li7  1  0.772  0.647  0.929  1.0
  Nb  Nb8  1  0.916  0.250  0.222  1.0
  Nb  Nb9  1  0.584  0.750  0.222  1.0
  Nb  Nb10  1  0.416  0.250  0.778  1.0
  Nb  Nb11  1  0.084  0.750  0.778  1.0
  P  P12  1  0.526  0.258  0.182  1.0
  P  P13  1  0.974  0.758  0.182  1.0
  P  P14  1  0.354  0.460  0.357  1.0
  P  P15  1  0.146  0.960  0.357  1.0
  P  P16  1  0.854  0.040  0.643  1.0
  P  P17  1  0.646  0.540  0.643  1.0
  P  P18  1  0.026  0.242  0.818  1.0
  P  P19  1  0.474  0.742  0.818  1.0
  O  O20  1  0.035  0.273  0.009  1.0
  O  O21  1  0.465  0.773  0.009  1.0
  O  O22  1  0.807  0.337  0.082  1.0
  O  O23  1  0.693  0.837  0.082  1.0
  O  O24  1  0.407  0.339  0.206  1.0
  O  O25  1  0.538  0.049  0.309  1.0
  O  O26  1  0.601  0.422  0.234  1.0
  O  O27  1  0.257  0.003  0.284  1.0
  O  O28  1  0.093  0.839  0.206  1.0
  O  O29  1  0.962  0.549  0.309  1.0
  O  O30  1  0.899  0.922  0.234  1.0
  O  O31  1  0.243  0.503  0.284  1.0
  O  O32  1  0.078  0.154  0.367  1.0
  O  O33  1  0.422  0.654  0.367  1.0
  O  O34  1  0.854  0.206  0.477  1.0
  O  O35  1  0.646  0.706  0.477  1.0
  O  O36  1  0.354  0.294  0.523  1.0
  O  O37  1  0.146  0.794  0.523  1.0
  O  O38  1  0.578  0.346  0.633  1.0
  O  O39  1  0.922  0.846  0.633  1.0
  O  O40  1  0.757  0.497  0.716  1.0
  O  O41  1  0.101  0.078  0.766  1.0
  O  O42  1  0.038  0.451  0.691  1.0
  O  O43  1  0.907  0.161  0.794  1.0
  O  O44  1  0.743  0.997  0.716  1.0
  O  O45  1  0.399  0.578  0.766  1.0
  O  O46  1  0.462  0.951  0.691  1.0
  O  O47  1  0.593  0.661  0.794  1.0
  O  O48  1  0.307  0.163  0.918  1.0
  O  O49  1  0.193  0.663  0.918  1.0
  O  O50  1  0.535  0.227  0.991  1.0
  O  O51  1  0.965  0.727  0.991  1.0
[/CIF]
.
The material described by Li2Nb(PO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(6) atoms. In the second Li site, Li(2) is bonded to one O(6), one O(7), one O(8), and two equivalent O(4) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, edges with two equivalent Nb(1)O6 octahedra, and  an edgeedge with one Li(2)O5 trigonal bipyramid. Nb(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form distorted NbO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and edges with two equivalent Li(2)O5 trigonal bipyramids. 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 three equivalent Nb(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Li(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 48-57°. In the second P site, P(2) is bonded to one O(3), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Li(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 40-52°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Li(2), one Nb(1), and one P(2) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Li(2), one Nb(1), and one P(2) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Li(1), one Nb(1), and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Li(1) and one Nb(1) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one P(1), and one P(2) atom. In the sixth O site, O(4) is bonded to two equivalent Li(2), one Nb(1), and one P(1) atom to form distorted edge-sharing OLi2NbP tetrahedra. In the seventh O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Nb(1) and one P(1) atom. In the eighth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), two equivalent Li(1), and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Nb(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.612
_cell_length_b   6.441
_cell_length_c   7.779
_cell_angle_alpha   81.127
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   624.392
_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  0.228  0.353  0.071  1.0
  Li  Li1  1  0.272  0.853  0.071  1.0
  Li  Li2  1  0.622  0.060  0.553  1.0
  Li  Li3  1  0.122  0.440  0.447  1.0
  Li  Li4  1  0.878  0.560  0.553  1.0
  Li  Li5  1  0.378  0.940  0.447  1.0
  Li  Li6  1  0.728  0.147  0.929  1.0
  Li  Li7  1  0.772  0.647  0.929  1.0
  Nb  Nb8  1  0.916  0.250  0.222  1.0
  Nb  Nb9  1  0.584  0.750  0.222  1.0
  Nb  Nb10  1  0.416  0.250  0.778  1.0
  Nb  Nb11  1  0.084  0.750  0.778  1.0
  P  P12  1  0.526  0.258  0.182  1.0
  P  P13  1  0.974  0.758  0.182  1.0
  P  P14  1  0.354  0.460  0.357  1.0
  P  P15  1  0.146  0.960  0.357  1.0
  P  P16  1  0.854  0.040  0.643  1.0
  P  P17  1  0.646  0.540  0.643  1.0
  P  P18  1  0.026  0.242  0.818  1.0
  P  P19  1  0.474  0.742  0.818  1.0
  O  O20  1  0.035  0.273  0.009  1.0
  O  O21  1  0.465  0.773  0.009  1.0
  O  O22  1  0.807  0.337  0.082  1.0
  O  O23  1  0.693  0.837  0.082  1.0
  O  O24  1  0.407  0.339  0.206  1.0
  O  O25  1  0.538  0.049  0.309  1.0
  O  O26  1  0.601  0.422  0.234  1.0
  O  O27  1  0.257  0.003  0.284  1.0
  O  O28  1  0.093  0.839  0.206  1.0
  O  O29  1  0.962  0.549  0.309  1.0
  O  O30  1  0.899  0.922  0.234  1.0
  O  O31  1  0.243  0.503  0.284  1.0
  O  O32  1  0.078  0.154  0.367  1.0
  O  O33  1  0.422  0.654  0.367  1.0
  O  O34  1  0.854  0.206  0.477  1.0
  O  O35  1  0.646  0.706  0.477  1.0
  O  O36  1  0.354  0.294  0.523  1.0
  O  O37  1  0.146  0.794  0.523  1.0
  O  O38  1  0.578  0.346  0.633  1.0
  O  O39  1  0.922  0.846  0.633  1.0
  O  O40  1  0.757  0.497  0.716  1.0
  O  O41  1  0.101  0.078  0.766  1.0
  O  O42  1  0.038  0.451  0.691  1.0
  O  O43  1  0.907  0.161  0.794  1.0
  O  O44  1  0.743  0.997  0.716  1.0
  O  O45  1  0.399  0.578  0.766  1.0
  O  O46  1  0.462  0.951  0.691  1.0
  O  O47  1  0.593  0.661  0.794  1.0
  O  O48  1  0.307  0.163  0.918  1.0
  O  O49  1  0.193  0.663  0.918  1.0
  O  O50  1  0.535  0.227  0.991  1.0
  O  O51  1  0.965  0.727  0.991  1.0
[/CIF]
.