MgZn2(NiO2)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. Zn(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ni(2), one Ni(3), one Ni(4), and one Zn(1) atom to form OZnNi3 tetrahedra that share corners with three equivalent O(3)MgZnNi3 square pyramids, corners with three equivalent O(4)MgZnNi3 square pyramids, corners with three equivalent O(1)ZnNi3 tetrahedra, corners with three equivalent O(2)MgZnNi3 trigonal bipyramids,  an edgeedge with one O(3)MgZnNi3 square pyramid,  an edgeedge with one O(4)MgZnNi3 square pyramid, and  an edgeedge with one O(2)MgZnNi3 trigonal bipyramid. In the second O site, O(2) is bonded to one Mg(1), one Ni(1), one Ni(3), one Ni(4), and one Zn(1) atom to form OMgZnNi3 trigonal bipyramids that share  a cornercorner with one O(3)MgZnNi3 square pyramid,  a cornercorner with one O(4)MgZnNi3 square pyramid, corners with three equivalent O(1)ZnNi3 tetrahedra, corners with four equivalent O(2)MgZnNi3 trigonal bipyramids, edges with three equivalent O(3)MgZnNi3 square pyramids, edges with three equivalent O(4)MgZnNi3 square pyramids, and  an edgeedge with one O(1)ZnNi3 tetrahedra. In the third O site, O(3) is bonded to one Mg(1), one Ni(1), one Ni(2), one Ni(4), and one Zn(1) atom to form OMgZnNi3 square pyramids that share  a cornercorner with one O(4)MgZnNi3 square pyramid, corners with four equivalent O(3)MgZnNi3 square pyramids, corners with three equivalent O(1)ZnNi3 tetrahedra,  a cornercorner with one O(2)MgZnNi3 trigonal bipyramid, edges with three equivalent O(4)MgZnNi3 square pyramids,  an edgeedge with one O(1)ZnNi3 tetrahedra, and edges with three equivalent O(2)MgZnNi3 trigonal bipyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Ni(1), one Ni(2), one Ni(3), and one Zn(1) atom to form OMgZnNi3 square pyramids that share  a cornercorner with one O(3)MgZnNi3 square pyramid, corners with four equivalent O(4)MgZnNi3 square pyramids, corners with three equivalent O(1)ZnNi3 tetrahedra,  a cornercorner with one O(2)MgZnNi3 trigonal bipyramid, edges with three equivalent O(3)MgZnNi3 square pyramids,  an edgeedge with one O(1)ZnNi3 tetrahedra, and edges with three equivalent O(2)MgZnNi3 trigonal bipyramids.
MgZn2(NiO2)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. Both Mg(1)-O(2) bond lengths are 2.13 Å. Both Mg(1)-O(3) bond lengths are 2.07 Å. Both Mg(1)-O(4) bond lengths are 2.13 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. Both Ni(1)-O(2) bond lengths are 2.17 Å. Both Ni(1)-O(3) bond lengths are 2.12 Å. Both Ni(1)-O(4) bond lengths are 2.17 Å. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. Both Ni(2)-O(1) bond lengths are 1.89 Å. Both Ni(2)-O(3) bond lengths are 2.19 Å. Both Ni(2)-O(4) bond lengths are 1.96 Å. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. Both Ni(3)-O(1) bond lengths are 1.97 Å. Both Ni(3)-O(2) bond lengths are 2.11 Å. Both Ni(3)-O(4) bond lengths are 2.12 Å. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. Both Ni(4)-O(1) bond lengths are 1.89 Å. Both Ni(4)-O(2) bond lengths are 1.96 Å. Both Ni(4)-O(3) bond lengths are 2.19 Å. Zn(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Zn(1)-O(1) bond length is 1.87 Å. The Zn(1)-O(2) bond length is 2.09 Å. The Zn(1)-O(3) bond length is 2.04 Å. The Zn(1)-O(4) bond length is 2.09 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ni(2), one Ni(3), one Ni(4), and one Zn(1) atom to form OZnNi3 tetrahedra that share corners with three equivalent O(3)MgZnNi3 square pyramids, corners with three equivalent O(4)MgZnNi3 square pyramids, corners with three equivalent O(1)ZnNi3 tetrahedra, corners with three equivalent O(2)MgZnNi3 trigonal bipyramids,  an edgeedge with one O(3)MgZnNi3 square pyramid,  an edgeedge with one O(4)MgZnNi3 square pyramid, and  an edgeedge with one O(2)MgZnNi3 trigonal bipyramid. In the second O site, O(2) is bonded to one Mg(1), one Ni(1), one Ni(3), one Ni(4), and one Zn(1) atom to form OMgZnNi3 trigonal bipyramids that share  a cornercorner with one O(3)MgZnNi3 square pyramid,  a cornercorner with one O(4)MgZnNi3 square pyramid, corners with three equivalent O(1)ZnNi3 tetrahedra, corners with four equivalent O(2)MgZnNi3 trigonal bipyramids, edges with three equivalent O(3)MgZnNi3 square pyramids, edges with three equivalent O(4)MgZnNi3 square pyramids, and  an edgeedge with one O(1)ZnNi3 tetrahedra. In the third O site, O(3) is bonded to one Mg(1), one Ni(1), one Ni(2), one Ni(4), and one Zn(1) atom to form OMgZnNi3 square pyramids that share  a cornercorner with one O(4)MgZnNi3 square pyramid, corners with four equivalent O(3)MgZnNi3 square pyramids, corners with three equivalent O(1)ZnNi3 tetrahedra,  a cornercorner with one O(2)MgZnNi3 trigonal bipyramid, edges with three equivalent O(4)MgZnNi3 square pyramids,  an edgeedge with one O(1)ZnNi3 tetrahedra, and edges with three equivalent O(2)MgZnNi3 trigonal bipyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Ni(1), one Ni(2), one Ni(3), and one Zn(1) atom to form OMgZnNi3 square pyramids that share  a cornercorner with one O(3)MgZnNi3 square pyramid, corners with four equivalent O(4)MgZnNi3 square pyramids, corners with three equivalent O(1)ZnNi3 tetrahedra,  a cornercorner with one O(2)MgZnNi3 trigonal bipyramid, edges with three equivalent O(3)MgZnNi3 square pyramids,  an edgeedge with one O(1)ZnNi3 tetrahedra, and edges with three equivalent O(2)MgZnNi3 trigonal bipyramids.