MgZn2(NiO2)4 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one Zn(1), one O(4), and four equivalent O(2) atoms to form distorted MgZnO5 square pyramids that share corners with four equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, corners with two equivalent O(4)MgZn2Ni2 trigonal bipyramids, corners with two equivalent O(5)ZnNi4 trigonal bipyramids, edges with two equivalent Mg(1)ZnO5 square pyramids, and faces with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(5) atoms to form NiO6 octahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Mg(1)ZnO5 square pyramids, edges with two equivalent Ni(1)O6 octahedra, and edges with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 20-68°. In the second Ni site, Ni(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form distorted NiO6 octahedra that share  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Mg(1)ZnO5 square pyramids, edges with two equivalent Ni(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and  a faceface with one Mg(1)ZnO5 square pyramid. The corner-sharing octahedral tilt angles range from 20-24°. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent O(4), and two equivalent O(5) atoms. In the second Zn site, Zn(2) is bonded in a 6-coordinate geometry to two equivalent O(3) and four equivalent O(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ni(2), two equivalent Ni(1), and two equivalent Zn(2) atoms to form OZn2Ni3 square pyramids that share corners with two equivalent O(1)Zn2Ni3 square pyramids, corners with four equivalent O(3)Zn2Ni2 tetrahedra,  a cornercorner with one O(4)MgZn2Ni2 trigonal bipyramid, corners with four equivalent O(5)ZnNi4 trigonal bipyramids, edges with three equivalent O(1)Zn2Ni3 square pyramids,  an edgeedge with one O(3)Zn2Ni2 tetrahedra, and  an edgeedge with one O(5)ZnNi4 trigonal bipyramid. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Ni(1), and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to two equivalent Ni(1) and two equivalent Zn(2) atoms to form OZn2Ni2 tetrahedra that share corners with eight equivalent O(1)Zn2Ni3 square pyramids, corners with two equivalent O(3)Zn2Ni2 tetrahedra, corners with four equivalent O(5)ZnNi4 trigonal bipyramids, and edges with two equivalent O(1)Zn2Ni3 square pyramids. In the fourth O site, O(4) is bonded to one Mg(1), two equivalent Ni(2), and two equivalent Zn(1) atoms to form distorted OMgZn2Ni2 trigonal bipyramids that share corners with two equivalent Mg(1)ZnO5 square pyramids, corners with two equivalent O(1)Zn2Ni3 square pyramids, corners with two equivalent O(4)MgZn2Ni2 trigonal bipyramids, and edges with four equivalent O(5)ZnNi4 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Ni(1), two equivalent Ni(2), and one Zn(1) atom to form OZnNi4 trigonal bipyramids that share  a cornercorner with one Mg(1)ZnO5 square pyramid, corners with four equivalent O(1)Zn2Ni3 square pyramids, corners with two equivalent O(3)Zn2Ni2 tetrahedra,  a cornercorner with one O(5)ZnNi4 trigonal bipyramid,  an edgeedge with one O(1)Zn2Ni3 square pyramid, edges with two equivalent O(4)MgZn2Ni2 trigonal bipyramids, and edges with two equivalent O(5)ZnNi4 trigonal bipyramids.
MgZn2(NiO2)4 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one Zn(1), one O(4), and four equivalent O(2) atoms to form distorted MgZnO5 square pyramids that share corners with four equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, corners with two equivalent O(4)MgZn2Ni2 trigonal bipyramids, corners with two equivalent O(5)ZnNi4 trigonal bipyramids, edges with two equivalent Mg(1)ZnO5 square pyramids, and faces with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. The Mg(1)-Zn(1) bond length is 2.41 Å. The Mg(1)-O(4) bond length is 1.90 Å. There are two shorter (2.06 Å) and two longer (2.08 Å) Mg(1)-O(2) bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(5) atoms to form NiO6 octahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Mg(1)ZnO5 square pyramids, edges with two equivalent Ni(1)O6 octahedra, and edges with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 20-68°. The Ni(1)-O(2) bond length is 2.00 Å. The Ni(1)-O(3) bond length is 2.05 Å. There is one shorter (2.15 Å) and one longer (2.21 Å) Ni(1)-O(1) bond length. There is one shorter (2.12 Å) and one longer (2.21 Å) Ni(1)-O(5) bond length. In the second Ni site, Ni(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form distorted NiO6 octahedra that share  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Mg(1)ZnO5 square pyramids, edges with two equivalent Ni(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and  a faceface with one Mg(1)ZnO5 square pyramid. The corner-sharing octahedral tilt angles range from 20-24°. The Ni(2)-O(1) bond length is 1.97 Å. The Ni(2)-O(4) bond length is 2.09 Å. There is one shorter (2.16 Å) and one longer (2.17 Å) Ni(2)-O(2) bond length. There is one shorter (2.10 Å) and one longer (2.13 Å) Ni(2)-O(5) bond length. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent O(4), and two equivalent O(5) atoms. There is one shorter (1.84 Å) and one longer (1.85 Å) Zn(1)-O(4) bond length. Both Zn(1)-O(5) bond lengths are 2.19 Å. In the second Zn site, Zn(2) is bonded in a 6-coordinate geometry to two equivalent O(3) and four equivalent O(1) atoms. There is one shorter (2.05 Å) and one longer (2.07 Å) Zn(2)-O(3) bond length. There are two shorter (2.28 Å) and two longer (2.32 Å) Zn(2)-O(1) bond lengths. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ni(2), two equivalent Ni(1), and two equivalent Zn(2) atoms to form OZn2Ni3 square pyramids that share corners with two equivalent O(1)Zn2Ni3 square pyramids, corners with four equivalent O(3)Zn2Ni2 tetrahedra,  a cornercorner with one O(4)MgZn2Ni2 trigonal bipyramid, corners with four equivalent O(5)ZnNi4 trigonal bipyramids, edges with three equivalent O(1)Zn2Ni3 square pyramids,  an edgeedge with one O(3)Zn2Ni2 tetrahedra, and  an edgeedge with one O(5)ZnNi4 trigonal bipyramid. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Ni(1), and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to two equivalent Ni(1) and two equivalent Zn(2) atoms to form OZn2Ni2 tetrahedra that share corners with eight equivalent O(1)Zn2Ni3 square pyramids, corners with two equivalent O(3)Zn2Ni2 tetrahedra, corners with four equivalent O(5)ZnNi4 trigonal bipyramids, and edges with two equivalent O(1)Zn2Ni3 square pyramids. In the fourth O site, O(4) is bonded to one Mg(1), two equivalent Ni(2), and two equivalent Zn(1) atoms to form distorted OMgZn2Ni2 trigonal bipyramids that share corners with two equivalent Mg(1)ZnO5 square pyramids, corners with two equivalent O(1)Zn2Ni3 square pyramids, corners with two equivalent O(4)MgZn2Ni2 trigonal bipyramids, and edges with four equivalent O(5)ZnNi4 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Ni(1), two equivalent Ni(2), and one Zn(1) atom to form OZnNi4 trigonal bipyramids that share  a cornercorner with one Mg(1)ZnO5 square pyramid, corners with four equivalent O(1)Zn2Ni3 square pyramids, corners with two equivalent O(3)Zn2Ni2 tetrahedra,  a cornercorner with one O(5)ZnNi4 trigonal bipyramid,  an edgeedge with one O(1)Zn2Ni3 square pyramid, edges with two equivalent O(4)MgZn2Ni2 trigonal bipyramids, and edges with two equivalent O(5)ZnNi4 trigonal bipyramids.