ZnCo2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Zn(2)O6 pentagonal pyramids, corners with three equivalent Zn(1)O6 pentagonal pyramids, edges with two equivalent Co(1)O6 octahedra, edges with four equivalent Co(2)O6 octahedra,  an edgeedge with one Zn(1)O6 pentagonal pyramid, and  a faceface with one Zn(2)O6 pentagonal pyramid. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with four equivalent Zn(2)O6 pentagonal pyramids, edges with two equivalent Co(2)O6 octahedra, edges with four equivalent Co(1)O6 octahedra, and edges with two equivalent Zn(1)O6 pentagonal pyramids. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form distorted ZnO6 pentagonal pyramids that share corners with six equivalent Co(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with four equivalent Co(2)O6 octahedra, and edges with two equivalent Zn(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 3-13°. In the second Zn site, Zn(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form distorted ZnO6 pentagonal pyramids that share corners with four equivalent Co(1)O6 octahedra, corners with eight equivalent Co(2)O6 octahedra, edges with two equivalent Zn(1)O6 pentagonal pyramids, and faces with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Co(1), two equivalent Co(2), and one Zn(1) atom. In the second O site, O(2) is bonded to one Co(1), two equivalent Co(2), and one Zn(2) atom to form OZnCo3 trigonal pyramids that share corners with four equivalent O(3)Zn2Co3 trigonal bipyramids, corners with three equivalent O(2)ZnCo3 trigonal pyramids, and edges with four equivalent O(3)Zn2Co3 trigonal bipyramids. In the third O site, O(3) is bonded to one Co(2), two equivalent Co(1), one Zn(1), and one Zn(2) atom to form OZn2Co3 trigonal bipyramids that share corners with five equivalent O(3)Zn2Co3 trigonal bipyramids, corners with two equivalent O(2)ZnCo3 trigonal pyramids, edges with four equivalent O(3)Zn2Co3 trigonal bipyramids, and edges with two equivalent O(2)ZnCo3 trigonal pyramids.
ZnCo2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Zn(2)O6 pentagonal pyramids, corners with three equivalent Zn(1)O6 pentagonal pyramids, edges with two equivalent Co(1)O6 octahedra, edges with four equivalent Co(2)O6 octahedra,  an edgeedge with one Zn(1)O6 pentagonal pyramid, and  a faceface with one Zn(2)O6 pentagonal pyramid. The Co(1)-O(1) bond length is 1.90 Å. The Co(1)-O(2) bond length is 2.03 Å. There are two shorter (2.01 Å) and two longer (2.13 Å) Co(1)-O(3) bond lengths. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with four equivalent Zn(2)O6 pentagonal pyramids, edges with two equivalent Co(2)O6 octahedra, edges with four equivalent Co(1)O6 octahedra, and edges with two equivalent Zn(1)O6 pentagonal pyramids. Both Co(2)-O(1) bond lengths are 2.00 Å. Both Co(2)-O(2) bond lengths are 2.01 Å. Both Co(2)-O(3) bond lengths are 2.05 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form distorted ZnO6 pentagonal pyramids that share corners with six equivalent Co(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with four equivalent Co(2)O6 octahedra, and edges with two equivalent Zn(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 3-13°. Both Zn(1)-O(1) bond lengths are 2.12 Å. All Zn(1)-O(3) bond lengths are 2.21 Å. In the second Zn site, Zn(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form distorted ZnO6 pentagonal pyramids that share corners with four equivalent Co(1)O6 octahedra, corners with eight equivalent Co(2)O6 octahedra, edges with two equivalent Zn(1)O6 pentagonal pyramids, and faces with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. Both Zn(2)-O(2) bond lengths are 2.18 Å. All Zn(2)-O(3) bond lengths are 2.21 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Co(1), two equivalent Co(2), and one Zn(1) atom. In the second O site, O(2) is bonded to one Co(1), two equivalent Co(2), and one Zn(2) atom to form OZnCo3 trigonal pyramids that share corners with four equivalent O(3)Zn2Co3 trigonal bipyramids, corners with three equivalent O(2)ZnCo3 trigonal pyramids, and edges with four equivalent O(3)Zn2Co3 trigonal bipyramids. In the third O site, O(3) is bonded to one Co(2), two equivalent Co(1), one Zn(1), and one Zn(2) atom to form OZn2Co3 trigonal bipyramids that share corners with five equivalent O(3)Zn2Co3 trigonal bipyramids, corners with two equivalent O(2)ZnCo3 trigonal pyramids, edges with four equivalent O(3)Zn2Co3 trigonal bipyramids, and edges with two equivalent O(2)ZnCo3 trigonal pyramids.