Li2Ni(PO4)2 crystallizes in the monoclinic Cm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. In the second Li site, Li(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted LiO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 69-81°. Ni(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Li(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(5), one O(6), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-55°. In the second P site, P(2) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and corners with two equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-53°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Ni(1), and one P(1) atom to form distorted edge-sharing OLi2NiP tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(2), one Ni(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Li(1) and one P(1) atom.
Li2Ni(PO4)2 crystallizes in the monoclinic Cm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. The Li(1)-O(2) bond length is 2.13 Å. The Li(1)-O(6) bond length is 2.06 Å. Both Li(1)-O(1) bond lengths are 2.25 Å. Both Li(1)-O(4) bond lengths are 2.18 Å. In the second Li site, Li(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted LiO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 69-81°. The Li(2)-O(2) bond length is 1.97 Å. The Li(2)-O(3) bond length is 2.00 Å. Both Li(2)-O(1) bond lengths are 2.10 Å. Ni(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Li(1)O6 octahedra. The Ni(1)-O(3) bond length is 2.05 Å. The Ni(1)-O(5) bond length is 2.02 Å. Both Ni(1)-O(1) bond lengths are 2.11 Å. Both Ni(1)-O(4) bond lengths are 2.07 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(5), one O(6), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-55°. The P(1)-O(5) bond length is 1.55 Å. The P(1)-O(6) bond length is 1.54 Å. Both P(1)-O(1) bond lengths are 1.55 Å. In the second P site, P(2) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and corners with two equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-53°. The P(2)-O(2) bond length is 1.55 Å. The P(2)-O(3) bond length is 1.56 Å. Both P(2)-O(4) bond lengths are 1.55 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Ni(1), and one P(1) atom to form distorted edge-sharing OLi2NiP tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(2), one Ni(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Li(1) and one P(1) atom.