ZnCr2O4 is Spinel-like structured and crystallizes in the trigonal P3m1 space group. There are six inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form CrO6 octahedra that share  a cornercorner with one Cr(6)O4 tetrahedra,  a cornercorner with one Zn(2)O4 tetrahedra, corners with two equivalent Cr(4)O4 tetrahedra, corners with two equivalent Zn(1)O4 tetrahedra,  an edgeedge with one Zn(3)O6 octahedra,  an edgeedge with one Zn(5)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to one O(10), one O(5), two equivalent O(3), and two equivalent O(8) atoms to form CrO6 octahedra that share  a cornercorner with one Cr(4)O4 tetrahedra,  a cornercorner with one Zn(4)O4 tetrahedra, corners with two equivalent Zn(2)O4 tetrahedra, corners with two equivalent Zn(6)O4 tetrahedra,  an edgeedge with one Cr(3)O6 octahedra,  an edgeedge with one Zn(3)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. In the third Cr site, Cr(3) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form CrO6 octahedra that share corners with three equivalent Zn(4)O4 tetrahedra, corners with three equivalent Zn(6)O4 tetrahedra, edges with three equivalent Cr(2)O6 octahedra, and edges with three equivalent Cr(5)O6 octahedra. In the fourth Cr site, Cr(4) is bonded to one O(10) and three equivalent O(4) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(2)O6 octahedra, corners with three equivalent Zn(3)O6 octahedra, and corners with six equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-61°. In the fifth Cr site, Cr(5) is bonded to one O(12), one O(9), two equivalent O(11), and two equivalent O(7) atoms to form CrO6 octahedra that share  a cornercorner with one Zn(1)O4 tetrahedra,  a cornercorner with one Zn(6)O4 tetrahedra, corners with two equivalent Cr(6)O4 tetrahedra, corners with two equivalent Zn(4)O4 tetrahedra,  an edgeedge with one Cr(3)O6 octahedra,  an edgeedge with one Zn(5)O6 octahedra, and edges with four equivalent Cr(5)O6 octahedra. In the sixth Cr site, Cr(6) is bonded to one O(6) and three equivalent O(11) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Zn(5)O6 octahedra, and corners with six equivalent Cr(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-61°. There are six inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(9) and three equivalent O(1) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(5)O6 octahedra, corners with three equivalent Zn(5)O6 octahedra, and corners with six equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. In the second Zn site, Zn(2) is bonded to one O(2) and three equivalent O(3) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Zn(3)O6 octahedra, and corners with six equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. In the third Zn site, Zn(3) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(4)O4 tetrahedra, corners with three equivalent Zn(2)O4 tetrahedra, edges with three equivalent Cr(1)O6 octahedra, and edges with three equivalent Cr(2)O6 octahedra. In the fourth Zn site, Zn(4) is bonded to one O(5) and three equivalent O(7) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(2)O6 octahedra, corners with three equivalent Cr(3)O6 octahedra, and corners with six equivalent Cr(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 58-60°. In the fifth Zn site, Zn(5) is bonded to three equivalent O(1) and three equivalent O(11) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(6)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, edges with three equivalent Cr(1)O6 octahedra, and edges with three equivalent Cr(5)O6 octahedra. In the sixth Zn site, Zn(6) is bonded to one O(12) and three equivalent O(8) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(3)O6 octahedra, corners with three equivalent Cr(5)O6 octahedra, and corners with six equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(1), one Zn(1), and one Zn(5) atom. In the second O site, O(2) is bonded to three equivalent Cr(1) and one Zn(2) atom to form distorted corner-sharing OZnCr3 trigonal pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(2), one Zn(2), and one Zn(3) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Cr(4), two equivalent Cr(1), and one Zn(3) atom. In the fifth O site, O(5) is bonded to three equivalent Cr(2) and one Zn(4) atom to form distorted OZnCr3 trigonal pyramids that share corners with three equivalent O(10)Cr4 trigonal pyramids, corners with three equivalent O(7)ZnCr3 trigonal pyramids, and corners with six equivalent O(8)ZnCr3 trigonal pyramids. In the sixth O site, O(6) is bonded to one Cr(6) and three equivalent Cr(1) atoms to form distorted corner-sharing OCr4 trigonal pyramids. In the seventh O site, O(7) is bonded to one Cr(3), two equivalent Cr(5), and one Zn(4) atom to form a mixture of distorted corner and edge-sharing OZnCr3 trigonal pyramids. In the eighth O site, O(8) is bonded to one Cr(3), two equivalent Cr(2), and one Zn(6) atom to form distorted OZnCr3 trigonal pyramids that share  a cornercorner with one O(12)ZnCr3 trigonal pyramid, corners with two equivalent O(5)ZnCr3 trigonal pyramids, corners with two equivalent O(8)ZnCr3 trigonal pyramids, corners with three equivalent O(7)ZnCr3 trigonal pyramids,  an edgeedge with one O(10)Cr4 trigonal pyramid, and edges with two equivalent O(8)ZnCr3 trigonal pyramids. In the ninth O site, O(9) is bonded to three equivalent Cr(5) and one Zn(1) atom to form a mixture of distorted corner and edge-sharing OZnCr3 trigonal pyramids. In the tenth O site, O(10) is bonded to one Cr(4) and three equivalent Cr(2) atoms to form a mixture of distorted corner and edge-sharing OCr4 trigonal pyramids. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Cr(6), two equivalent Cr(5), and one Zn(5) atom. In the twelfth O site, O(12) is bonded to three equivalent Cr(5) and one Zn(6) atom to form distorted corner-sharing OZnCr3 trigonal pyramids.
ZnCr2O4 is Spinel-like structured and crystallizes in the trigonal P3m1 space group. There are six inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form CrO6 octahedra that share  a cornercorner with one Cr(6)O4 tetrahedra,  a cornercorner with one Zn(2)O4 tetrahedra, corners with two equivalent Cr(4)O4 tetrahedra, corners with two equivalent Zn(1)O4 tetrahedra,  an edgeedge with one Zn(3)O6 octahedra,  an edgeedge with one Zn(5)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. The Cr(1)-O(2) bond length is 2.03 Å. The Cr(1)-O(6) bond length is 2.06 Å. Both Cr(1)-O(1) bond lengths are 2.01 Å. Both Cr(1)-O(4) bond lengths are 2.04 Å. In the second Cr site, Cr(2) is bonded to one O(10), one O(5), two equivalent O(3), and two equivalent O(8) atoms to form CrO6 octahedra that share  a cornercorner with one Cr(4)O4 tetrahedra,  a cornercorner with one Zn(4)O4 tetrahedra, corners with two equivalent Zn(2)O4 tetrahedra, corners with two equivalent Zn(6)O4 tetrahedra,  an edgeedge with one Cr(3)O6 octahedra,  an edgeedge with one Zn(3)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. The Cr(2)-O(10) bond length is 2.06 Å. The Cr(2)-O(5) bond length is 2.03 Å. Both Cr(2)-O(3) bond lengths are 2.01 Å. Both Cr(2)-O(8) bond lengths are 2.04 Å. In the third Cr site, Cr(3) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form CrO6 octahedra that share corners with three equivalent Zn(4)O4 tetrahedra, corners with three equivalent Zn(6)O4 tetrahedra, edges with three equivalent Cr(2)O6 octahedra, and edges with three equivalent Cr(5)O6 octahedra. All Cr(3)-O(7) bond lengths are 2.04 Å. All Cr(3)-O(8) bond lengths are 2.01 Å. In the fourth Cr site, Cr(4) is bonded to one O(10) and three equivalent O(4) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(2)O6 octahedra, corners with three equivalent Zn(3)O6 octahedra, and corners with six equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-61°. The Cr(4)-O(10) bond length is 2.05 Å. All Cr(4)-O(4) bond lengths are 1.93 Å. In the fifth Cr site, Cr(5) is bonded to one O(12), one O(9), two equivalent O(11), and two equivalent O(7) atoms to form CrO6 octahedra that share  a cornercorner with one Zn(1)O4 tetrahedra,  a cornercorner with one Zn(6)O4 tetrahedra, corners with two equivalent Cr(6)O4 tetrahedra, corners with two equivalent Zn(4)O4 tetrahedra,  an edgeedge with one Cr(3)O6 octahedra,  an edgeedge with one Zn(5)O6 octahedra, and edges with four equivalent Cr(5)O6 octahedra. The Cr(5)-O(12) bond length is 2.03 Å. The Cr(5)-O(9) bond length is 2.04 Å. Both Cr(5)-O(11) bond lengths are 2.05 Å. Both Cr(5)-O(7) bond lengths are 2.02 Å. In the sixth Cr site, Cr(6) is bonded to one O(6) and three equivalent O(11) atoms to form CrO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Zn(5)O6 octahedra, and corners with six equivalent Cr(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-61°. The Cr(6)-O(6) bond length is 2.05 Å. All Cr(6)-O(11) bond lengths are 1.93 Å. There are six inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(9) and three equivalent O(1) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(5)O6 octahedra, corners with three equivalent Zn(5)O6 octahedra, and corners with six equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. The Zn(1)-O(9) bond length is 2.08 Å. All Zn(1)-O(1) bond lengths are 1.98 Å. In the second Zn site, Zn(2) is bonded to one O(2) and three equivalent O(3) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Zn(3)O6 octahedra, and corners with six equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. The Zn(2)-O(2) bond length is 2.08 Å. All Zn(2)-O(3) bond lengths are 1.97 Å. In the third Zn site, Zn(3) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(4)O4 tetrahedra, corners with three equivalent Zn(2)O4 tetrahedra, edges with three equivalent Cr(1)O6 octahedra, and edges with three equivalent Cr(2)O6 octahedra. All Zn(3)-O(3) bond lengths are 2.08 Å. All Zn(3)-O(4) bond lengths are 2.16 Å. In the fourth Zn site, Zn(4) is bonded to one O(5) and three equivalent O(7) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(2)O6 octahedra, corners with three equivalent Cr(3)O6 octahedra, and corners with six equivalent Cr(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 58-60°. The Zn(4)-O(5) bond length is 1.99 Å. All Zn(4)-O(7) bond lengths are 2.02 Å. In the fifth Zn site, Zn(5) is bonded to three equivalent O(1) and three equivalent O(11) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(6)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, edges with three equivalent Cr(1)O6 octahedra, and edges with three equivalent Cr(5)O6 octahedra. All Zn(5)-O(1) bond lengths are 2.08 Å. All Zn(5)-O(11) bond lengths are 2.17 Å. In the sixth Zn site, Zn(6) is bonded to one O(12) and three equivalent O(8) atoms to form ZnO4 tetrahedra that share corners with three equivalent Cr(3)O6 octahedra, corners with three equivalent Cr(5)O6 octahedra, and corners with six equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. The Zn(6)-O(12) bond length is 2.06 Å. All Zn(6)-O(8) bond lengths are 2.00 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(1), one Zn(1), and one Zn(5) atom. In the second O site, O(2) is bonded to three equivalent Cr(1) and one Zn(2) atom to form distorted corner-sharing OZnCr3 trigonal pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(2), one Zn(2), and one Zn(3) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Cr(4), two equivalent Cr(1), and one Zn(3) atom. In the fifth O site, O(5) is bonded to three equivalent Cr(2) and one Zn(4) atom to form distorted OZnCr3 trigonal pyramids that share corners with three equivalent O(10)Cr4 trigonal pyramids, corners with three equivalent O(7)ZnCr3 trigonal pyramids, and corners with six equivalent O(8)ZnCr3 trigonal pyramids. In the sixth O site, O(6) is bonded to one Cr(6) and three equivalent Cr(1) atoms to form distorted corner-sharing OCr4 trigonal pyramids. In the seventh O site, O(7) is bonded to one Cr(3), two equivalent Cr(5), and one Zn(4) atom to form a mixture of distorted corner and edge-sharing OZnCr3 trigonal pyramids. In the eighth O site, O(8) is bonded to one Cr(3), two equivalent Cr(2), and one Zn(6) atom to form distorted OZnCr3 trigonal pyramids that share  a cornercorner with one O(12)ZnCr3 trigonal pyramid, corners with two equivalent O(5)ZnCr3 trigonal pyramids, corners with two equivalent O(8)ZnCr3 trigonal pyramids, corners with three equivalent O(7)ZnCr3 trigonal pyramids,  an edgeedge with one O(10)Cr4 trigonal pyramid, and edges with two equivalent O(8)ZnCr3 trigonal pyramids. In the ninth O site, O(9) is bonded to three equivalent Cr(5) and one Zn(1) atom to form a mixture of distorted corner and edge-sharing OZnCr3 trigonal pyramids. In the tenth O site, O(10) is bonded to one Cr(4) and three equivalent Cr(2) atoms to form a mixture of distorted corner and edge-sharing OCr4 trigonal pyramids. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Cr(6), two equivalent Cr(5), and one Zn(5) atom. In the twelfth O site, O(12) is bonded to three equivalent Cr(5) and one Zn(6) atom to form distorted corner-sharing OZnCr3 trigonal pyramids.