MgCo2(NiO2)4 is Aluminum carbonitride-derived structured and crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Ni(2)O6 octahedra, corners with two equivalent Co(1)O4 tetrahedra, and  an edgeedge with one Co(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-64°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form CoO4 tetrahedra that share corners with six equivalent Ni(2)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-70°. In the second Co site, Co(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted CoO4 tetrahedra that share corners with six equivalent Ni(2)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-72°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(1), and two equivalent O(4) atoms. In the second Ni site, Ni(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, and edges with two equivalent Ni(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Mg(1), one Co(1), one Ni(2), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Co(1), one Ni(1), and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to one Mg(1), one Co(2), and two equivalent Ni(2) atoms to form distorted OMgCoNi2 tetrahedra that share corners with four equivalent O(4)CoNi3 tetrahedra and edges with two equivalent O(3)MgCoNi2 tetrahedra. In the fourth O site, O(4) is bonded to one Co(2), one Ni(2), and two equivalent Ni(1) atoms to form OCoNi3 tetrahedra that share  a cornercorner with one O(4)CoNi3 tetrahedra, corners with four equivalent O(3)MgCoNi2 tetrahedra, and  an edgeedge with one O(4)CoNi3 tetrahedra.
MgCo2(NiO2)4 is Aluminum carbonitride-derived structured and crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Ni(2)O6 octahedra, corners with two equivalent Co(1)O4 tetrahedra, and  an edgeedge with one Co(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-64°. Both Mg(1)-O(1) bond lengths are 1.99 Å. Both Mg(1)-O(3) bond lengths are 1.91 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form CoO4 tetrahedra that share corners with six equivalent Ni(2)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-70°. Both Co(1)-O(1) bond lengths are 1.92 Å. Both Co(1)-O(2) bond lengths are 1.93 Å. In the second Co site, Co(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted CoO4 tetrahedra that share corners with six equivalent Ni(2)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-72°. Both Co(2)-O(3) bond lengths are 2.01 Å. Both Co(2)-O(4) bond lengths are 1.83 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(1), and two equivalent O(4) atoms. The Ni(1)-O(2) bond length is 1.97 Å. There is one shorter (2.15 Å) and one longer (2.16 Å) Ni(1)-O(1) bond length. Both Ni(1)-O(4) bond lengths are 1.99 Å. In the second Ni site, Ni(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, and edges with two equivalent Ni(2)O6 octahedra. The Ni(2)-O(1) bond length is 2.16 Å. The Ni(2)-O(4) bond length is 2.07 Å. Both Ni(2)-O(2) bond lengths are 2.15 Å. Both Ni(2)-O(3) bond lengths are 2.10 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Mg(1), one Co(1), one Ni(2), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Co(1), one Ni(1), and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to one Mg(1), one Co(2), and two equivalent Ni(2) atoms to form distorted OMgCoNi2 tetrahedra that share corners with four equivalent O(4)CoNi3 tetrahedra and edges with two equivalent O(3)MgCoNi2 tetrahedra. In the fourth O site, O(4) is bonded to one Co(2), one Ni(2), and two equivalent Ni(1) atoms to form OCoNi3 tetrahedra that share  a cornercorner with one O(4)CoNi3 tetrahedra, corners with four equivalent O(3)MgCoNi2 tetrahedra, and  an edgeedge with one O(4)CoNi3 tetrahedra.