Mg2MoMn3S8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form MgS4 tetrahedra that share corners with three equivalent Mo(1)S6 octahedra, corners with three equivalent Mn(1)S6 octahedra, and corners with six equivalent Mn(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-59°. Mo(1) is bonded to two equivalent S(2) and four equivalent S(3) atoms to form MoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with four equivalent Mn(2)S6 octahedra. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent S(1) and four equivalent S(3) atoms to form MnS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mo(1)S6 octahedra, and edges with four equivalent Mn(2)S6 octahedra. In the second Mn site, Mn(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form MnS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mo(1)S6 octahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with two equivalent Mn(2)S6 octahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one Mn(1), and two equivalent Mn(2) atoms to form distorted SMgMn3 trigonal pyramids that share corners with three equivalent S(2)MgMn2Mo trigonal pyramids, corners with three equivalent S(1)MgMn3 trigonal pyramids, corners with six equivalent S(3)MgMn2Mo trigonal pyramids,  an edgeedge with one S(2)MgMn2Mo trigonal pyramid, and edges with two equivalent S(3)MgMn2Mo trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one Mo(1), and two equivalent Mn(2) atoms to form distorted SMgMn2Mo trigonal pyramids that share corners with three equivalent S(2)MgMn2Mo trigonal pyramids, corners with three equivalent S(1)MgMn3 trigonal pyramids, corners with six equivalent S(3)MgMn2Mo trigonal pyramids,  an edgeedge with one S(1)MgMn3 trigonal pyramid, and edges with two equivalent S(3)MgMn2Mo trigonal pyramids. In the third S site, S(3) is bonded to one Mg(1), one Mo(1), one Mn(1), and one Mn(2) atom to form distorted SMgMn2Mo trigonal pyramids that share corners with three equivalent S(2)MgMn2Mo trigonal pyramids, corners with three equivalent S(1)MgMn3 trigonal pyramids, corners with six equivalent S(3)MgMn2Mo trigonal pyramids,  an edgeedge with one S(2)MgMn2Mo trigonal pyramid,  an edgeedge with one S(3)MgMn2Mo trigonal pyramid, and  an edgeedge with one S(1)MgMn3 trigonal pyramid.
Mg2MoMn3S8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form MgS4 tetrahedra that share corners with three equivalent Mo(1)S6 octahedra, corners with three equivalent Mn(1)S6 octahedra, and corners with six equivalent Mn(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-59°. The Mg(1)-S(1) bond length is 2.48 Å. The Mg(1)-S(2) bond length is 2.44 Å. Both Mg(1)-S(3) bond lengths are 2.45 Å. Mo(1) is bonded to two equivalent S(2) and four equivalent S(3) atoms to form MoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with four equivalent Mn(2)S6 octahedra. Both Mo(1)-S(2) bond lengths are 2.48 Å. All Mo(1)-S(3) bond lengths are 2.48 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent S(1) and four equivalent S(3) atoms to form MnS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mo(1)S6 octahedra, and edges with four equivalent Mn(2)S6 octahedra. Both Mn(1)-S(1) bond lengths are 2.46 Å. All Mn(1)-S(3) bond lengths are 2.50 Å. In the second Mn site, Mn(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form MnS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mo(1)S6 octahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with two equivalent Mn(2)S6 octahedra. Both Mn(2)-S(1) bond lengths are 2.46 Å. Both Mn(2)-S(2) bond lengths are 2.50 Å. Both Mn(2)-S(3) bond lengths are 2.50 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one Mn(1), and two equivalent Mn(2) atoms to form distorted SMgMn3 trigonal pyramids that share corners with three equivalent S(2)MgMn2Mo trigonal pyramids, corners with three equivalent S(1)MgMn3 trigonal pyramids, corners with six equivalent S(3)MgMn2Mo trigonal pyramids,  an edgeedge with one S(2)MgMn2Mo trigonal pyramid, and edges with two equivalent S(3)MgMn2Mo trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one Mo(1), and two equivalent Mn(2) atoms to form distorted SMgMn2Mo trigonal pyramids that share corners with three equivalent S(2)MgMn2Mo trigonal pyramids, corners with three equivalent S(1)MgMn3 trigonal pyramids, corners with six equivalent S(3)MgMn2Mo trigonal pyramids,  an edgeedge with one S(1)MgMn3 trigonal pyramid, and edges with two equivalent S(3)MgMn2Mo trigonal pyramids. In the third S site, S(3) is bonded to one Mg(1), one Mo(1), one Mn(1), and one Mn(2) atom to form distorted SMgMn2Mo trigonal pyramids that share corners with three equivalent S(2)MgMn2Mo trigonal pyramids, corners with three equivalent S(1)MgMn3 trigonal pyramids, corners with six equivalent S(3)MgMn2Mo trigonal pyramids,  an edgeedge with one S(2)MgMn2Mo trigonal pyramid,  an edgeedge with one S(3)MgMn2Mo trigonal pyramid, and  an edgeedge with one S(1)MgMn3 trigonal pyramid.