Zn(NiO2)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form NiO6 octahedra that share corners with four equivalent Ni(2)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with four equivalent Ni(1)O6 octahedra, and edges with three equivalent Zn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 51-57°. In the second Ni site, Ni(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form distorted NiO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra, corners with four equivalent Zn(1)O5 square pyramids, edges with four equivalent Ni(2)O6 octahedra, and  a faceface with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 51-57°. Zn(1) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form ZnO5 square pyramids that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, edges with two equivalent Zn(1)O5 square pyramids, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-58°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ni(2), two equivalent Ni(1), and one Zn(1) atom to form OZnNi3 trigonal pyramids that share corners with two equivalent O(3)Zn2Ni3 square pyramids, corners with two equivalent O(1)ZnNi3 trigonal pyramids, and edges with three equivalent O(3)Zn2Ni3 square pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ni(1) and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to three equivalent Ni(1) and two equivalent Zn(1) atoms to form OZn2Ni3 square pyramids that share corners with two equivalent O(1)ZnNi3 trigonal pyramids, edges with four equivalent O(3)Zn2Ni3 square pyramids, and edges with three equivalent O(1)ZnNi3 trigonal pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent Ni(2) and two equivalent Zn(1) atoms.
Zn(NiO2)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form NiO6 octahedra that share corners with four equivalent Ni(2)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with four equivalent Ni(1)O6 octahedra, and edges with three equivalent Zn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 51-57°. The Ni(1)-O(2) bond length is 1.85 Å. Both Ni(1)-O(1) bond lengths are 1.92 Å. There is one shorter (2.00 Å) and two longer (2.10 Å) Ni(1)-O(3) bond lengths. In the second Ni site, Ni(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form distorted NiO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra, corners with four equivalent Zn(1)O5 square pyramids, edges with four equivalent Ni(2)O6 octahedra, and  a faceface with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 51-57°. The Ni(2)-O(1) bond length is 1.96 Å. Both Ni(2)-O(2) bond lengths are 1.94 Å. There is one shorter (1.95 Å) and two longer (2.22 Å) Ni(2)-O(4) bond lengths. Zn(1) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form ZnO5 square pyramids that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, edges with two equivalent Zn(1)O5 square pyramids, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-58°. The Zn(1)-O(1) bond length is 2.12 Å. Both Zn(1)-O(3) bond lengths are 2.09 Å. Both Zn(1)-O(4) bond lengths are 2.04 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ni(2), two equivalent Ni(1), and one Zn(1) atom to form OZnNi3 trigonal pyramids that share corners with two equivalent O(3)Zn2Ni3 square pyramids, corners with two equivalent O(1)ZnNi3 trigonal pyramids, and edges with three equivalent O(3)Zn2Ni3 square pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ni(1) and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to three equivalent Ni(1) and two equivalent Zn(1) atoms to form OZn2Ni3 square pyramids that share corners with two equivalent O(1)ZnNi3 trigonal pyramids, edges with four equivalent O(3)Zn2Ni3 square pyramids, and edges with three equivalent O(1)ZnNi3 trigonal pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent Ni(2) and two equivalent Zn(1) atoms.