ZnCr2S4 crystallizes in the orthorhombic Imma space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form CrS6 octahedra that share edges with two equivalent Cr(1)S6 octahedra, edges with four equivalent Cr(2)S6 octahedra, and edges with four equivalent Zn(1)S6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form CrS6 octahedra that share corners with six equivalent Zn(1)S6 octahedra, edges with two equivalent Cr(2)S6 octahedra, edges with two equivalent Zn(1)S6 octahedra, and edges with four equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. Zn(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form ZnS6 octahedra that share corners with six equivalent Cr(2)S6 octahedra, edges with two equivalent Cr(2)S6 octahedra, edges with two equivalent Zn(1)S6 octahedra, and edges with four equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Cr(2), two equivalent Cr(1), and one Zn(1) atom. In the second S site, S(2) is bonded to one Cr(1), two equivalent Cr(2), and two equivalent Zn(1) atoms to form a mixture of corner and edge-sharing SZn2Cr3 square pyramids.
ZnCr2S4 crystallizes in the orthorhombic Imma space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form CrS6 octahedra that share edges with two equivalent Cr(1)S6 octahedra, edges with four equivalent Cr(2)S6 octahedra, and edges with four equivalent Zn(1)S6 octahedra. Both Cr(1)-S(2) bond lengths are 2.38 Å. All Cr(1)-S(1) bond lengths are 2.41 Å. In the second Cr site, Cr(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form CrS6 octahedra that share corners with six equivalent Zn(1)S6 octahedra, edges with two equivalent Cr(2)S6 octahedra, edges with two equivalent Zn(1)S6 octahedra, and edges with four equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. Both Cr(2)-S(1) bond lengths are 2.43 Å. All Cr(2)-S(2) bond lengths are 2.45 Å. Zn(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form ZnS6 octahedra that share corners with six equivalent Cr(2)S6 octahedra, edges with two equivalent Cr(2)S6 octahedra, edges with two equivalent Zn(1)S6 octahedra, and edges with four equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. Both Zn(1)-S(1) bond lengths are 2.44 Å. All Zn(1)-S(2) bond lengths are 2.61 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Cr(2), two equivalent Cr(1), and one Zn(1) atom. In the second S site, S(2) is bonded to one Cr(1), two equivalent Cr(2), and two equivalent Zn(1) atoms to form a mixture of corner and edge-sharing SZn2Cr3 square pyramids.