Li2Nb(PO4)2 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(1), one O(3), one O(4), and two equivalent O(2) atoms to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 59°. Nb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 37-48°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Nb(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Li(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Nb(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Nb(1), and one P(1) atom.
Li2Nb(PO4)2 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(1), one O(3), one O(4), and two equivalent O(2) atoms to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 59°. The Li(1)-O(1) bond length is 2.18 Å. The Li(1)-O(3) bond length is 2.21 Å. The Li(1)-O(4) bond length is 2.15 Å. There is one shorter (1.87 Å) and one longer (1.93 Å) Li(1)-O(2) bond length. Nb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. Both Nb(1)-O(1) bond lengths are 2.15 Å. Both Nb(1)-O(3) bond lengths are 2.07 Å. Both Nb(1)-O(4) bond lengths are 2.05 Å. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 37-48°. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(2) bond length is 1.50 Å. The P(1)-O(3) bond length is 1.57 Å. The P(1)-O(4) bond length is 1.58 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Nb(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Li(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Nb(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Nb(1), and one P(1) atom.