MgPm2S4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one S(2), one S(3), and two equivalent S(1) atoms to form MgS4 tetrahedra that share corners with two equivalent Pm(1)S6 octahedra, corners with four equivalent Pm(2)S6 octahedra,  an edgeedge with one Pm(2)S6 octahedra, and edges with two equivalent Pm(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-64°. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form PmS6 octahedra that share corners with four equivalent Pm(2)S6 octahedra, corners with two equivalent Mg(1)S4 tetrahedra, edges with two equivalent Pm(1)S6 octahedra, edges with two equivalent Pm(2)S6 octahedra, and edges with two equivalent Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-58°. In the second Pm site, Pm(2) is bonded to one S(2), one S(3), and four equivalent S(1) atoms to form PmS6 octahedra that share corners with four equivalent Pm(1)S6 octahedra, corners with four equivalent Pm(2)S6 octahedra, corners with four equivalent Mg(1)S4 tetrahedra, edges with two equivalent Pm(1)S6 octahedra, and  an edgeedge with one Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-58°. There are three inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Pm(1), and two equivalent Pm(2) atoms. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Pm(2), and two equivalent Pm(1) atoms. In the third S site, S(3) is bonded to one Mg(1), one Pm(2), and two equivalent Pm(1) atoms to form distorted corner-sharing SPm3Mg trigonal pyramids.
MgPm2S4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one S(2), one S(3), and two equivalent S(1) atoms to form MgS4 tetrahedra that share corners with two equivalent Pm(1)S6 octahedra, corners with four equivalent Pm(2)S6 octahedra,  an edgeedge with one Pm(2)S6 octahedra, and edges with two equivalent Pm(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-64°. The Mg(1)-S(2) bond length is 2.47 Å. The Mg(1)-S(3) bond length is 2.40 Å. Both Mg(1)-S(1) bond lengths are 2.46 Å. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form PmS6 octahedra that share corners with four equivalent Pm(2)S6 octahedra, corners with two equivalent Mg(1)S4 tetrahedra, edges with two equivalent Pm(1)S6 octahedra, edges with two equivalent Pm(2)S6 octahedra, and edges with two equivalent Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-58°. Both Pm(1)-S(1) bond lengths are 2.84 Å. Both Pm(1)-S(2) bond lengths are 2.81 Å. Both Pm(1)-S(3) bond lengths are 2.79 Å. In the second Pm site, Pm(2) is bonded to one S(2), one S(3), and four equivalent S(1) atoms to form PmS6 octahedra that share corners with four equivalent Pm(1)S6 octahedra, corners with four equivalent Pm(2)S6 octahedra, corners with four equivalent Mg(1)S4 tetrahedra, edges with two equivalent Pm(1)S6 octahedra, and  an edgeedge with one Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-58°. The Pm(2)-S(2) bond length is 2.80 Å. The Pm(2)-S(3) bond length is 2.84 Å. There are two shorter (2.84 Å) and two longer (2.89 Å) Pm(2)-S(1) bond lengths. There are three inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Pm(1), and two equivalent Pm(2) atoms. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Pm(2), and two equivalent Pm(1) atoms. In the third S site, S(3) is bonded to one Mg(1), one Pm(2), and two equivalent Pm(1) atoms to form distorted corner-sharing SPm3Mg trigonal pyramids.