Li6NiO4 crystallizes in the orthorhombic P2_12_12 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Ni(1)O4 tetrahedra, and edges with two equivalent Li(2)O4 tetrahedra. In the second Li site, Li(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Ni(1)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. In the third Li site, Li(3) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O4 tetrahedra, and edges with two equivalent Li(4)O4 tetrahedra. In the fourth Li site, Li(4) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O4 tetrahedra, and edges with two equivalent Li(3)O4 tetrahedra. Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted NiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(3)O4 tetrahedra, corners with four equivalent Li(4)O4 tetrahedra, edges with two equivalent Li(1)O4 tetrahedra, and edges with two equivalent Li(2)O4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Li(3), one Li(4), two equivalent Li(1), two equivalent Li(2), and one Ni(1) atom to form a mixture of distorted edge and corner-sharing OLi6Ni pentagonal bipyramids. In the second O site, O(2) is bonded to one Li(3), one Li(4), two equivalent Li(1), two equivalent Li(2), and one Ni(1) atom to form a mixture of distorted edge and corner-sharing OLi6Ni pentagonal bipyramids.
Li6NiO4 crystallizes in the orthorhombic P2_12_12 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Ni(1)O4 tetrahedra, and edges with two equivalent Li(2)O4 tetrahedra. There is one shorter (2.04 Å) and one longer (2.07 Å) Li(1)-O(1) bond length. There is one shorter (2.03 Å) and one longer (2.07 Å) Li(1)-O(2) bond length. In the second Li site, Li(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra,  an edgeedge with one Li(3)O4 tetrahedra,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Ni(1)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. There is one shorter (1.97 Å) and one longer (2.14 Å) Li(2)-O(1) bond length. There is one shorter (1.97 Å) and one longer (2.13 Å) Li(2)-O(2) bond length. In the third Li site, Li(3) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O4 tetrahedra, and edges with two equivalent Li(4)O4 tetrahedra. Both Li(3)-O(1) bond lengths are 1.98 Å. Both Li(3)-O(2) bond lengths are 1.91 Å. In the fourth Li site, Li(4) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O4 tetrahedra, and edges with two equivalent Li(3)O4 tetrahedra. Both Li(4)-O(1) bond lengths are 1.91 Å. Both Li(4)-O(2) bond lengths are 1.98 Å. Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted NiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(3)O4 tetrahedra, corners with four equivalent Li(4)O4 tetrahedra, edges with two equivalent Li(1)O4 tetrahedra, and edges with two equivalent Li(2)O4 tetrahedra. Both Ni(1)-O(1) bond lengths are 1.99 Å. Both Ni(1)-O(2) bond lengths are 2.00 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Li(3), one Li(4), two equivalent Li(1), two equivalent Li(2), and one Ni(1) atom to form a mixture of distorted edge and corner-sharing OLi6Ni pentagonal bipyramids. In the second O site, O(2) is bonded to one Li(3), one Li(4), two equivalent Li(1), two equivalent Li(2), and one Ni(1) atom to form a mixture of distorted edge and corner-sharing OLi6Ni pentagonal bipyramids.