Li2FeNi3O8 is Spinel-derived structured and crystallizes in the hexagonal P6_3mc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3) and three equivalent O(2) atoms to form LiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and corners with nine equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. In the second Li site, Li(2) is bonded to one O(4) and three equivalent O(1) atoms to form LiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and edges with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-64°. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and edges with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. Ni(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with four equivalent Ni(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Li(2), one Fe(1), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded to one Li(1), one Fe(1), and two equivalent Ni(1) atoms to form distorted OLiFeNi2 tetrahedra that share  a cornercorner with one O(3)LiNi3 tetrahedra, corners with two equivalent O(2)LiFeNi2 tetrahedra, corners with two equivalent O(4)LiNi3 tetrahedra,  an edgeedge with one O(3)LiNi3 tetrahedra, and edges with two equivalent O(2)LiFeNi2 tetrahedra. In the third O site, O(3) is bonded to one Li(1) and three equivalent Ni(1) atoms to form distorted OLiNi3 tetrahedra that share corners with three equivalent O(2)LiFeNi2 tetrahedra, corners with three equivalent O(4)LiNi3 tetrahedra, and edges with three equivalent O(2)LiFeNi2 tetrahedra. In the fourth O site, O(4) is bonded to one Li(2) and three equivalent Ni(1) atoms to form OLiNi3 tetrahedra that share corners with three equivalent O(3)LiNi3 tetrahedra and corners with six equivalent O(2)LiFeNi2 tetrahedra.
Li2FeNi3O8 is Spinel-derived structured and crystallizes in the hexagonal P6_3mc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3) and three equivalent O(2) atoms to form LiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and corners with nine equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. The Li(1)-O(3) bond length is 1.98 Å. All Li(1)-O(2) bond lengths are 1.90 Å. In the second Li site, Li(2) is bonded to one O(4) and three equivalent O(1) atoms to form LiO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and edges with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-64°. The Li(2)-O(4) bond length is 1.74 Å. All Li(2)-O(1) bond lengths are 1.87 Å. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and edges with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Fe(1)-O(1) bond lengths are 1.87 Å. All Fe(1)-O(2) bond lengths are 1.94 Å. Ni(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with four equivalent Ni(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. The Ni(1)-O(3) bond length is 1.85 Å. The Ni(1)-O(4) bond length is 1.87 Å. Both Ni(1)-O(1) bond lengths are 2.00 Å. Both Ni(1)-O(2) bond lengths are 1.95 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Li(2), one Fe(1), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded to one Li(1), one Fe(1), and two equivalent Ni(1) atoms to form distorted OLiFeNi2 tetrahedra that share  a cornercorner with one O(3)LiNi3 tetrahedra, corners with two equivalent O(2)LiFeNi2 tetrahedra, corners with two equivalent O(4)LiNi3 tetrahedra,  an edgeedge with one O(3)LiNi3 tetrahedra, and edges with two equivalent O(2)LiFeNi2 tetrahedra. In the third O site, O(3) is bonded to one Li(1) and three equivalent Ni(1) atoms to form distorted OLiNi3 tetrahedra that share corners with three equivalent O(2)LiFeNi2 tetrahedra, corners with three equivalent O(4)LiNi3 tetrahedra, and edges with three equivalent O(2)LiFeNi2 tetrahedra. In the fourth O site, O(4) is bonded to one Li(2) and three equivalent Ni(1) atoms to form OLiNi3 tetrahedra that share corners with three equivalent O(3)LiNi3 tetrahedra and corners with six equivalent O(2)LiFeNi2 tetrahedra.