ZnCrO2 crystallizes in the triclinic P1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), two equivalent O(4), and two equivalent O(5) atoms to form CrO5 square pyramids that share corners with two equivalent Cr(2)O5 square pyramids, corners with two equivalent Cr(3)O5 square pyramids, corners with two equivalent Zn(1)O5 trigonal bipyramids, corners with two equivalent Zn(2)O5 trigonal bipyramids, edges with two equivalent Cr(1)O5 square pyramids, and  an edgeedge with one Zn(2)O5 trigonal bipyramid. In the second Cr site, Cr(2) is bonded to one O(4), two equivalent O(3), and two equivalent O(6) atoms to form distorted CrO5 square pyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids, corners with two equivalent Zn(1)O5 trigonal bipyramids, edges with two equivalent Cr(2)O5 square pyramids, and  a faceface with one Zn(1)O5 trigonal bipyramid. In the third Cr site, Cr(3) is bonded to one O(1), two equivalent O(2), and two equivalent O(8) atoms to form distorted CrO5 square pyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids, corners with two equivalent Zn(2)O5 trigonal bipyramids, edges with two equivalent Cr(3)O5 square pyramids, and  a faceface with one Zn(2)O5 trigonal bipyramid. In the fourth Cr site, Cr(4) is bonded to one O(3), two equivalent O(1), and two equivalent O(7) atoms to form CrO5 square pyramids that share corners with two equivalent Cr(2)O5 square pyramids, corners with two equivalent Cr(3)O5 square pyramids, corners with two equivalent Zn(1)O5 trigonal bipyramids, corners with two equivalent Zn(2)O5 trigonal bipyramids, edges with two equivalent Cr(4)O5 square pyramids, and  an edgeedge with one Zn(1)O5 trigonal bipyramid. There are four inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(4), two equivalent O(6), and two equivalent O(7) atoms to form distorted ZnO5 trigonal bipyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(2)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids,  an edgeedge with one Cr(4)O5 square pyramid, edges with two equivalent Zn(1)O5 trigonal bipyramids, and  a faceface with one Cr(2)O5 square pyramid. In the second Zn site, Zn(2) is bonded to one O(1), two equivalent O(5), and two equivalent O(8) atoms to form distorted ZnO5 trigonal bipyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(3)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids,  an edgeedge with one Cr(1)O5 square pyramid, edges with two equivalent Zn(2)O5 trigonal bipyramids, and  a faceface with one Cr(3)O5 square pyramid. In the third Zn site, Zn(3) is bonded in a water-like geometry to one O(7) and one O(8) atom. In the fourth Zn site, Zn(4) is bonded in a water-like geometry to one O(5) and one O(6) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Cr(3), two equivalent Cr(4), and one Zn(2) atom to form distorted OZnCr3 tetrahedra that share corners with two equivalent O(1)ZnCr3 tetrahedra, corners with two equivalent O(5)Zn3Cr2 trigonal bipyramids, corners with two equivalent O(7)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(7)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(8)Zn3Cr2 trigonal bipyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Cr(1) and two equivalent Cr(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Cr(4) and two equivalent Cr(2) atoms. In the fourth O site, O(4) is bonded to one Cr(2), two equivalent Cr(1), and one Zn(1) atom to form distorted OZnCr3 tetrahedra that share corners with two equivalent O(4)ZnCr3 tetrahedra, corners with two equivalent O(5)Zn3Cr2 trigonal bipyramids, corners with two equivalent O(7)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(5)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(6)Zn3Cr2 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Cr(1), one Zn(4), and two equivalent Zn(2) atoms to form distorted OZn3Cr2 trigonal bipyramids that share corners with two equivalent O(1)ZnCr3 tetrahedra, corners with two equivalent O(4)ZnCr3 tetrahedra,  a cornercorner with one O(6)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(8)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(4)ZnCr3 tetrahedra,  an edgeedge with one O(8)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(5)Zn3Cr2 trigonal bipyramids. In the sixth O site, O(6) is bonded to two equivalent Cr(2), one Zn(4), and two equivalent Zn(1) atoms to form distorted OZn3Cr2 trigonal bipyramids that share  a cornercorner with one O(5)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(7)Zn3Cr2 trigonal bipyramids, edges with two equivalent O(4)ZnCr3 tetrahedra,  an edgeedge with one O(7)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(6)Zn3Cr2 trigonal bipyramids. In the seventh O site, O(7) is bonded to two equivalent Cr(4), one Zn(3), and two equivalent Zn(1) atoms to form distorted OZn3Cr2 trigonal bipyramids that share corners with two equivalent O(1)ZnCr3 tetrahedra, corners with two equivalent O(4)ZnCr3 tetrahedra,  a cornercorner with one O(8)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(6)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(1)ZnCr3 tetrahedra,  an edgeedge with one O(6)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(7)Zn3Cr2 trigonal bipyramids. In the eighth O site, O(8) is bonded to two equivalent Cr(3), one Zn(3), and two equivalent Zn(2) atoms to form distorted OZn3Cr2 trigonal bipyramids that share  a cornercorner with one O(7)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(5)Zn3Cr2 trigonal bipyramids, edges with two equivalent O(1)ZnCr3 tetrahedra,  an edgeedge with one O(5)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(8)Zn3Cr2 trigonal bipyramids.
ZnCrO2 crystallizes in the triclinic P1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), two equivalent O(4), and two equivalent O(5) atoms to form CrO5 square pyramids that share corners with two equivalent Cr(2)O5 square pyramids, corners with two equivalent Cr(3)O5 square pyramids, corners with two equivalent Zn(1)O5 trigonal bipyramids, corners with two equivalent Zn(2)O5 trigonal bipyramids, edges with two equivalent Cr(1)O5 square pyramids, and  an edgeedge with one Zn(2)O5 trigonal bipyramid. The Cr(1)-O(2) bond length is 2.01 Å. Both Cr(1)-O(4) bond lengths are 1.99 Å. There is one shorter (2.17 Å) and one longer (2.19 Å) Cr(1)-O(5) bond length. In the second Cr site, Cr(2) is bonded to one O(4), two equivalent O(3), and two equivalent O(6) atoms to form distorted CrO5 square pyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids, corners with two equivalent Zn(1)O5 trigonal bipyramids, edges with two equivalent Cr(2)O5 square pyramids, and  a faceface with one Zn(1)O5 trigonal bipyramid. The Cr(2)-O(4) bond length is 2.04 Å. Both Cr(2)-O(3) bond lengths are 1.92 Å. There is one shorter (2.15 Å) and one longer (2.16 Å) Cr(2)-O(6) bond length. In the third Cr site, Cr(3) is bonded to one O(1), two equivalent O(2), and two equivalent O(8) atoms to form distorted CrO5 square pyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids, corners with two equivalent Zn(2)O5 trigonal bipyramids, edges with two equivalent Cr(3)O5 square pyramids, and  a faceface with one Zn(2)O5 trigonal bipyramid. The Cr(3)-O(1) bond length is 2.03 Å. Both Cr(3)-O(2) bond lengths are 1.92 Å. There is one shorter (2.14 Å) and one longer (2.15 Å) Cr(3)-O(8) bond length. In the fourth Cr site, Cr(4) is bonded to one O(3), two equivalent O(1), and two equivalent O(7) atoms to form CrO5 square pyramids that share corners with two equivalent Cr(2)O5 square pyramids, corners with two equivalent Cr(3)O5 square pyramids, corners with two equivalent Zn(1)O5 trigonal bipyramids, corners with two equivalent Zn(2)O5 trigonal bipyramids, edges with two equivalent Cr(4)O5 square pyramids, and  an edgeedge with one Zn(1)O5 trigonal bipyramid. The Cr(4)-O(3) bond length is 2.01 Å. Both Cr(4)-O(1) bond lengths are 1.99 Å. There is one shorter (2.17 Å) and one longer (2.19 Å) Cr(4)-O(7) bond length. There are four inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(4), two equivalent O(6), and two equivalent O(7) atoms to form distorted ZnO5 trigonal bipyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(2)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids,  an edgeedge with one Cr(4)O5 square pyramid, edges with two equivalent Zn(1)O5 trigonal bipyramids, and  a faceface with one Cr(2)O5 square pyramid. The Zn(1)-O(4) bond length is 2.07 Å. There is one shorter (2.11 Å) and one longer (2.23 Å) Zn(1)-O(6) bond length. There is one shorter (2.08 Å) and one longer (2.15 Å) Zn(1)-O(7) bond length. In the second Zn site, Zn(2) is bonded to one O(1), two equivalent O(5), and two equivalent O(8) atoms to form distorted ZnO5 trigonal bipyramids that share corners with two equivalent Cr(1)O5 square pyramids, corners with two equivalent Cr(3)O5 square pyramids, corners with two equivalent Cr(4)O5 square pyramids,  an edgeedge with one Cr(1)O5 square pyramid, edges with two equivalent Zn(2)O5 trigonal bipyramids, and  a faceface with one Cr(3)O5 square pyramid. The Zn(2)-O(1) bond length is 2.07 Å. There is one shorter (2.07 Å) and one longer (2.14 Å) Zn(2)-O(5) bond length. There is one shorter (2.11 Å) and one longer (2.24 Å) Zn(2)-O(8) bond length. In the third Zn site, Zn(3) is bonded in a water-like geometry to one O(7) and one O(8) atom. The Zn(3)-O(7) bond length is 2.06 Å. The Zn(3)-O(8) bond length is 2.08 Å. In the fourth Zn site, Zn(4) is bonded in a water-like geometry to one O(5) and one O(6) atom. The Zn(4)-O(5) bond length is 2.07 Å. The Zn(4)-O(6) bond length is 2.08 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Cr(3), two equivalent Cr(4), and one Zn(2) atom to form distorted OZnCr3 tetrahedra that share corners with two equivalent O(1)ZnCr3 tetrahedra, corners with two equivalent O(5)Zn3Cr2 trigonal bipyramids, corners with two equivalent O(7)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(7)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(8)Zn3Cr2 trigonal bipyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Cr(1) and two equivalent Cr(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Cr(4) and two equivalent Cr(2) atoms. In the fourth O site, O(4) is bonded to one Cr(2), two equivalent Cr(1), and one Zn(1) atom to form distorted OZnCr3 tetrahedra that share corners with two equivalent O(4)ZnCr3 tetrahedra, corners with two equivalent O(5)Zn3Cr2 trigonal bipyramids, corners with two equivalent O(7)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(5)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(6)Zn3Cr2 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Cr(1), one Zn(4), and two equivalent Zn(2) atoms to form distorted OZn3Cr2 trigonal bipyramids that share corners with two equivalent O(1)ZnCr3 tetrahedra, corners with two equivalent O(4)ZnCr3 tetrahedra,  a cornercorner with one O(6)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(8)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(4)ZnCr3 tetrahedra,  an edgeedge with one O(8)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(5)Zn3Cr2 trigonal bipyramids. In the sixth O site, O(6) is bonded to two equivalent Cr(2), one Zn(4), and two equivalent Zn(1) atoms to form distorted OZn3Cr2 trigonal bipyramids that share  a cornercorner with one O(5)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(7)Zn3Cr2 trigonal bipyramids, edges with two equivalent O(4)ZnCr3 tetrahedra,  an edgeedge with one O(7)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(6)Zn3Cr2 trigonal bipyramids. In the seventh O site, O(7) is bonded to two equivalent Cr(4), one Zn(3), and two equivalent Zn(1) atoms to form distorted OZn3Cr2 trigonal bipyramids that share corners with two equivalent O(1)ZnCr3 tetrahedra, corners with two equivalent O(4)ZnCr3 tetrahedra,  a cornercorner with one O(8)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(6)Zn3Cr2 trigonal bipyramids,  an edgeedge with one O(1)ZnCr3 tetrahedra,  an edgeedge with one O(6)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(7)Zn3Cr2 trigonal bipyramids. In the eighth O site, O(8) is bonded to two equivalent Cr(3), one Zn(3), and two equivalent Zn(2) atoms to form distorted OZn3Cr2 trigonal bipyramids that share  a cornercorner with one O(7)Zn3Cr2 trigonal bipyramid, corners with two equivalent O(5)Zn3Cr2 trigonal bipyramids, edges with two equivalent O(1)ZnCr3 tetrahedra,  an edgeedge with one O(5)Zn3Cr2 trigonal bipyramid, and edges with two equivalent O(8)Zn3Cr2 trigonal bipyramids.