Cr2MnSe3S crystallizes in the monoclinic Cm space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(2), two equivalent Se(1), two equivalent Se(3), and one S(1) atom to form CrSe5S octahedra that share corners with six equivalent Mn(1)Se5S octahedra, edges with two equivalent Cr(1)Se5S octahedra, edges with four equivalent Cr(2)Se4S2 octahedra, and  a faceface with one Mn(1)Se5S octahedra. The corner-sharing octahedral tilt angles range from 50-52°. In the second Cr site, Cr(2) is bonded to one Se(1), one Se(3), two equivalent Se(2), and two equivalent S(1) atoms to form CrSe4S2 octahedra that share corners with six equivalent Mn(1)Se5S octahedra, edges with two equivalent Cr(2)Se4S2 octahedra, edges with four equivalent Cr(1)Se5S octahedra, and  a faceface with one Mn(1)Se5S octahedra. The corner-sharing octahedral tilt angles range from 47-50°. Mn(1) is bonded to one Se(1), two equivalent Se(2), two equivalent Se(3), and one S(1) atom to form MnSe5S octahedra that share corners with six equivalent Cr(2)Se4S2 octahedra, corners with six equivalent Cr(1)Se5S octahedra, edges with two equivalent Mn(1)Se5S octahedra,  a faceface with one Cr(2)Se4S2 octahedra, and  a faceface with one Cr(1)Se5S octahedra. The corner-sharing octahedral tilt angles range from 47-52°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(2), two equivalent Cr(1), and one Mn(1) atom. In the second Se site, Se(2) is bonded to one Cr(1), two equivalent Cr(2), and two equivalent Mn(1) atoms to form distorted SeMn2Cr3 trigonal bipyramids that share corners with two equivalent Se(3)Mn2Cr3 square pyramids, corners with five equivalent S(1)MnCr3 trigonal pyramids, edges with three equivalent Se(3)Mn2Cr3 square pyramids, edges with two equivalent Se(2)Mn2Cr3 trigonal bipyramids, and  an edgeedge with one S(1)MnCr3 trigonal pyramid. In the third Se site, Se(3) is bonded to one Cr(2), two equivalent Cr(1), and two equivalent Mn(1) atoms to form distorted SeMn2Cr3 square pyramids that share corners with two equivalent Se(2)Mn2Cr3 trigonal bipyramids, corners with two equivalent S(1)MnCr3 trigonal pyramids, edges with two equivalent Se(3)Mn2Cr3 square pyramids, edges with three equivalent Se(2)Mn2Cr3 trigonal bipyramids, and edges with two equivalent S(1)MnCr3 trigonal pyramids. S(1) is bonded to one Cr(1), two equivalent Cr(2), and one Mn(1) atom to form SMnCr3 trigonal pyramids that share corners with two equivalent Se(3)Mn2Cr3 square pyramids, corners with five equivalent Se(2)Mn2Cr3 trigonal bipyramids, corners with two equivalent S(1)MnCr3 trigonal pyramids, edges with two equivalent Se(3)Mn2Cr3 square pyramids, and  an edgeedge with one Se(2)Mn2Cr3 trigonal bipyramid.
Cr2MnSe3S crystallizes in the monoclinic Cm space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(2), two equivalent Se(1), two equivalent Se(3), and one S(1) atom to form CrSe5S octahedra that share corners with six equivalent Mn(1)Se5S octahedra, edges with two equivalent Cr(1)Se5S octahedra, edges with four equivalent Cr(2)Se4S2 octahedra, and  a faceface with one Mn(1)Se5S octahedra. The corner-sharing octahedral tilt angles range from 50-52°. The Cr(1)-Se(2) bond length is 2.59 Å. Both Cr(1)-Se(1) bond lengths are 2.51 Å. Both Cr(1)-Se(3) bond lengths are 2.62 Å. The Cr(1)-S(1) bond length is 2.41 Å. In the second Cr site, Cr(2) is bonded to one Se(1), one Se(3), two equivalent Se(2), and two equivalent S(1) atoms to form CrSe4S2 octahedra that share corners with six equivalent Mn(1)Se5S octahedra, edges with two equivalent Cr(2)Se4S2 octahedra, edges with four equivalent Cr(1)Se5S octahedra, and  a faceface with one Mn(1)Se5S octahedra. The corner-sharing octahedral tilt angles range from 47-50°. The Cr(2)-Se(1) bond length is 2.54 Å. The Cr(2)-Se(3) bond length is 2.62 Å. Both Cr(2)-Se(2) bond lengths are 2.63 Å. Both Cr(2)-S(1) bond lengths are 2.42 Å. Mn(1) is bonded to one Se(1), two equivalent Se(2), two equivalent Se(3), and one S(1) atom to form MnSe5S octahedra that share corners with six equivalent Cr(2)Se4S2 octahedra, corners with six equivalent Cr(1)Se5S octahedra, edges with two equivalent Mn(1)Se5S octahedra,  a faceface with one Cr(2)Se4S2 octahedra, and  a faceface with one Cr(1)Se5S octahedra. The corner-sharing octahedral tilt angles range from 47-52°. The Mn(1)-Se(1) bond length is 2.65 Å. Both Mn(1)-Se(2) bond lengths are 2.69 Å. Both Mn(1)-Se(3) bond lengths are 2.70 Å. The Mn(1)-S(1) bond length is 2.50 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(2), two equivalent Cr(1), and one Mn(1) atom. In the second Se site, Se(2) is bonded to one Cr(1), two equivalent Cr(2), and two equivalent Mn(1) atoms to form distorted SeMn2Cr3 trigonal bipyramids that share corners with two equivalent Se(3)Mn2Cr3 square pyramids, corners with five equivalent S(1)MnCr3 trigonal pyramids, edges with three equivalent Se(3)Mn2Cr3 square pyramids, edges with two equivalent Se(2)Mn2Cr3 trigonal bipyramids, and  an edgeedge with one S(1)MnCr3 trigonal pyramid. In the third Se site, Se(3) is bonded to one Cr(2), two equivalent Cr(1), and two equivalent Mn(1) atoms to form distorted SeMn2Cr3 square pyramids that share corners with two equivalent Se(2)Mn2Cr3 trigonal bipyramids, corners with two equivalent S(1)MnCr3 trigonal pyramids, edges with two equivalent Se(3)Mn2Cr3 square pyramids, edges with three equivalent Se(2)Mn2Cr3 trigonal bipyramids, and edges with two equivalent S(1)MnCr3 trigonal pyramids. S(1) is bonded to one Cr(1), two equivalent Cr(2), and one Mn(1) atom to form SMnCr3 trigonal pyramids that share corners with two equivalent Se(3)Mn2Cr3 square pyramids, corners with five equivalent Se(2)Mn2Cr3 trigonal bipyramids, corners with two equivalent S(1)MnCr3 trigonal pyramids, edges with two equivalent Se(3)Mn2Cr3 square pyramids, and  an edgeedge with one Se(2)Mn2Cr3 trigonal bipyramid.