ZnCr2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2) and three equivalent O(1) atoms to form CrO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(3) and three equivalent O(4) atoms to form ZnO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Zn site, Zn(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, and edges with six equivalent Cr(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(2), and one Zn(2) atom. In the second O site, O(2) is bonded to one Cr(1) and three equivalent Cr(2) atoms to form distorted corner-sharing OCr4 trigonal pyramids. In the third O site, O(3) is bonded to three equivalent Cr(2) and one Zn(1) atom to form distorted corner-sharing OZnCr3 trigonal pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(2), one Zn(1), and one Zn(2) atom.
ZnCr2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2) and three equivalent O(1) atoms to form CrO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. The Cr(1)-O(2) bond length is 2.09 Å. All Cr(1)-O(1) bond lengths are 1.93 Å. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. The Cr(2)-O(2) bond length is 2.05 Å. The Cr(2)-O(3) bond length is 2.04 Å. Both Cr(2)-O(1) bond lengths are 2.05 Å. Both Cr(2)-O(4) bond lengths are 2.00 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(3) and three equivalent O(4) atoms to form ZnO4 tetrahedra that share corners with three equivalent Zn(2)O6 octahedra and corners with nine equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. The Zn(1)-O(3) bond length is 2.07 Å. All Zn(1)-O(4) bond lengths are 1.98 Å. In the second Zn site, Zn(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Zn(1)O4 tetrahedra, and edges with six equivalent Cr(2)O6 octahedra. All Zn(2)-O(1) bond lengths are 2.15 Å. All Zn(2)-O(4) bond lengths are 2.09 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(2), and one Zn(2) atom. In the second O site, O(2) is bonded to one Cr(1) and three equivalent Cr(2) atoms to form distorted corner-sharing OCr4 trigonal pyramids. In the third O site, O(3) is bonded to three equivalent Cr(2) and one Zn(1) atom to form distorted corner-sharing OZnCr3 trigonal pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(2), one Zn(1), and one Zn(2) atom.