LiNiPO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(4), and two equivalent O(1) atoms. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(6), and one O(8) atom. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(6), and one O(8) atom to form NiO5 trigonal bipyramids that share corners with two equivalent Ni(2)O6 pentagonal pyramids, corners with two equivalent P(2)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. In the second Ni site, Ni(2) is bonded to one O(4), one O(6), one O(7), one O(8), and two equivalent O(5) atoms to form distorted NiO6 pentagonal pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with two equivalent Ni(1)O5 trigonal bipyramids,  an edgeedge with one Ni(2)O6 pentagonal pyramid, and  an edgeedge with one P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, 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  a cornercorner with one Ni(2)O6 pentagonal pyramid and corners with three equivalent Ni(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Ni(2)O6 pentagonal pyramids, corners with two equivalent Ni(1)O5 trigonal bipyramids, and  an edgeedge with one Ni(2)O6 pentagonal pyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Ni(1), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi2NiP trigonal pyramids. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Ni(1), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi2NiP tetrahedra. 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(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(1), one Ni(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Ni(2) and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Li(2), one Ni(1), one Ni(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ni(2) and one P(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Li(2), one Ni(1), one Ni(2), and one P(2) atom.
LiNiPO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(4), and two equivalent O(1) atoms. The Li(1)-O(2) bond length is 2.22 Å. The Li(1)-O(4) bond length is 2.09 Å. There is one shorter (2.12 Å) and one longer (2.25 Å) Li(1)-O(1) bond length. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(6), and one O(8) atom. The Li(2)-O(2) bond length is 2.06 Å. The Li(2)-O(3) bond length is 2.12 Å. The Li(2)-O(6) bond length is 2.28 Å. The Li(2)-O(8) bond length is 2.02 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(6), and one O(8) atom to form NiO5 trigonal bipyramids that share corners with two equivalent Ni(2)O6 pentagonal pyramids, corners with two equivalent P(2)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. The Ni(1)-O(1) bond length is 2.10 Å. The Ni(1)-O(2) bond length is 2.08 Å. The Ni(1)-O(3) bond length is 2.00 Å. The Ni(1)-O(6) bond length is 2.02 Å. The Ni(1)-O(8) bond length is 2.20 Å. In the second Ni site, Ni(2) is bonded to one O(4), one O(6), one O(7), one O(8), and two equivalent O(5) atoms to form distorted NiO6 pentagonal pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with two equivalent Ni(1)O5 trigonal bipyramids,  an edgeedge with one Ni(2)O6 pentagonal pyramid, and  an edgeedge with one P(2)O4 tetrahedra. The Ni(2)-O(4) bond length is 2.11 Å. The Ni(2)-O(6) bond length is 2.23 Å. The Ni(2)-O(7) bond length is 1.96 Å. The Ni(2)-O(8) bond length is 2.17 Å. There is one shorter (1.98 Å) and one longer (2.25 Å) Ni(2)-O(5) bond length. There are two inequivalent P sites. In the first P site, 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  a cornercorner with one Ni(2)O6 pentagonal pyramid and corners with three equivalent Ni(1)O5 trigonal bipyramids. The P(1)-O(1) bond length is 1.57 Å. The P(1)-O(2) bond length is 1.57 Å. The P(1)-O(3) bond length is 1.55 Å. The P(1)-O(4) bond length is 1.55 Å. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Ni(2)O6 pentagonal pyramids, corners with two equivalent Ni(1)O5 trigonal bipyramids, and  an edgeedge with one Ni(2)O6 pentagonal pyramid. The P(2)-O(5) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.57 Å. The P(2)-O(7) bond length is 1.53 Å. The P(2)-O(8) bond length is 1.57 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Ni(1), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi2NiP trigonal pyramids. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Ni(1), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi2NiP tetrahedra. 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(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(1), one Ni(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Ni(2) and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Li(2), one Ni(1), one Ni(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ni(2) and one P(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Li(2), one Ni(1), one Ni(2), and one P(2) atom.