Li3NiCPO7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), and one O(5) atom. In the second Li site, Li(2) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted LiO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra and edges with two equivalent Ni(1)O5 trigonal bipyramids. In the third Li site, Li(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and one O(7) atom. Ni(1) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form NiO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra and edges with two equivalent Li(2)O5 trigonal bipyramids. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Li(2)O5 trigonal bipyramids and corners with three equivalent Ni(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Ni(1), and one P(1) atom. In the second O site, O(7) is bonded to one Li(2), one Li(3), one Ni(1), and one P(1) atom to form OLi2NiP tetrahedra that share corners with three equivalent O(5)Li2NiP trigonal pyramids and  an edgeedge with one O(2)Li2NiC tetrahedra. In the third O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Li(1) and one C(1) atom. In the fourth O site, O(2) is bonded to one Li(1), one Li(2), one Ni(1), and one C(1) atom to form a mixture of distorted edge and corner-sharing OLi2NiC tetrahedra. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Li(2), one Li(3), one Ni(1), and one C(1) atom. In the sixth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Li(3), and one P(1) atom. In the seventh O site, O(5) is bonded to one Li(1), one Li(3), one Ni(1), and one P(1) atom to form distorted OLi2NiP trigonal pyramids that share corners with two equivalent O(2)Li2NiC tetrahedra and corners with three equivalent O(7)Li2NiP tetrahedra.
Li3NiCPO7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), and one O(5) atom. The Li(1)-O(1) bond length is 1.88 Å. The Li(1)-O(2) bond length is 1.97 Å. The Li(1)-O(4) bond length is 2.14 Å. The Li(1)-O(5) bond length is 2.22 Å. In the second Li site, Li(2) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted LiO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra and edges with two equivalent Ni(1)O5 trigonal bipyramids. The Li(2)-O(2) bond length is 2.34 Å. The Li(2)-O(3) bond length is 2.24 Å. The Li(2)-O(4) bond length is 1.97 Å. The Li(2)-O(6) bond length is 2.05 Å. The Li(2)-O(7) bond length is 2.21 Å. In the third Li site, Li(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Li(3)-O(3) bond length is 2.28 Å. The Li(3)-O(4) bond length is 1.97 Å. The Li(3)-O(5) bond length is 1.99 Å. The Li(3)-O(6) bond length is 2.18 Å. The Li(3)-O(7) bond length is 2.07 Å. Ni(1) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form NiO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra and edges with two equivalent Li(2)O5 trigonal bipyramids. The Ni(1)-O(2) bond length is 2.05 Å. The Ni(1)-O(3) bond length is 2.13 Å. The Ni(1)-O(5) bond length is 2.06 Å. The Ni(1)-O(6) bond length is 2.03 Å. The Ni(1)-O(7) bond length is 2.09 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(2) bond length is 1.32 Å. The C(1)-O(3) bond length is 1.30 Å. P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Li(2)O5 trigonal bipyramids and corners with three equivalent Ni(1)O5 trigonal bipyramids. The P(1)-O(4) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.56 Å. The P(1)-O(6) bond length is 1.54 Å. The P(1)-O(7) bond length is 1.56 Å. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Ni(1), and one P(1) atom. In the second O site, O(7) is bonded to one Li(2), one Li(3), one Ni(1), and one P(1) atom to form OLi2NiP tetrahedra that share corners with three equivalent O(5)Li2NiP trigonal pyramids and  an edgeedge with one O(2)Li2NiC tetrahedra. In the third O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Li(1) and one C(1) atom. In the fourth O site, O(2) is bonded to one Li(1), one Li(2), one Ni(1), and one C(1) atom to form a mixture of distorted edge and corner-sharing OLi2NiC tetrahedra. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Li(2), one Li(3), one Ni(1), and one C(1) atom. In the sixth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Li(3), and one P(1) atom. In the seventh O site, O(5) is bonded to one Li(1), one Li(3), one Ni(1), and one P(1) atom to form distorted OLi2NiP trigonal pyramids that share corners with two equivalent O(2)Li2NiC tetrahedra and corners with three equivalent O(7)Li2NiP tetrahedra.