Ni3O4 crystallizes in the monoclinic C2/m space group. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form edge-sharing NiO6 octahedra. In the second Ni site, Ni(2) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-20°. In the third Ni site, Ni(3) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-20°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ni(2) and three equivalent Ni(3) atoms to form a mixture of edge and corner-sharing ONi5 square pyramids. In the second O site, O(2) is bonded in a see-saw-like geometry to one Ni(2), one Ni(4), and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded to one Ni(1), two equivalent Ni(2), and two equivalent Ni(4) atoms to form a mixture of edge and corner-sharing ONi5 square pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Ni(2) and three equivalent Ni(3) atoms.
Ni3O4 crystallizes in the monoclinic C2/m space group. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form edge-sharing NiO6 octahedra. Both Ni(1)-O(3) bond lengths are 1.88 Å. All Ni(1)-O(2) bond lengths are 1.90 Å. In the second Ni site, Ni(2) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-20°. The Ni(2)-O(2) bond length is 2.07 Å. The Ni(2)-O(4) bond length is 2.00 Å. Both Ni(2)-O(1) bond lengths are 2.08 Å. Both Ni(2)-O(3) bond lengths are 2.10 Å. In the third Ni site, Ni(3) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-20°. All Ni(3)-O(1) bond lengths are 2.04 Å. There are two shorter (1.97 Å) and one longer (1.99 Å) Ni(3)-O(4) bond length. In the fourth Ni site, Ni(4) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. Both Ni(4)-O(2) bond lengths are 2.08 Å. All Ni(4)-O(3) bond lengths are 2.09 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ni(2) and three equivalent Ni(3) atoms to form a mixture of edge and corner-sharing ONi5 square pyramids. In the second O site, O(2) is bonded in a see-saw-like geometry to one Ni(2), one Ni(4), and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded to one Ni(1), two equivalent Ni(2), and two equivalent Ni(4) atoms to form a mixture of edge and corner-sharing ONi5 square pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Ni(2) and three equivalent Ni(3) atoms.