MgSm2S4 is Aluminum carbonitride-like structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one S(2), one S(3), one S(5), and one S(6) atom to form MgS4 tetrahedra that share corners with two equivalent Sm(2)S6 octahedra, corners with three equivalent Sm(1)S5 trigonal bipyramids, and corners with three equivalent Sm(4)S5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 66°. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one S(2), two equivalent S(1), and two equivalent S(8) atoms. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one S(1), one S(3), one S(4), one S(5), and one S(6) atom to form distorted SmS5 trigonal bipyramids that share  a cornercorner with one Sm(2)S6 octahedra, corners with three equivalent Mg(1)S4 tetrahedra, corners with two equivalent Sm(4)S5 trigonal bipyramids, and  an edgeedge with one Sm(4)S5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 65°. In the second Sm site, Sm(2) is bonded to one S(1), one S(8), two equivalent S(2), and two equivalent S(7) atoms to form SmS6 octahedra that share corners with two equivalent Mg(1)S4 tetrahedra,  a cornercorner with one Sm(1)S5 trigonal bipyramid, corners with two equivalent Sm(4)S5 trigonal bipyramids, and edges with two equivalent Sm(2)S6 octahedra. In the third Sm site, Sm(3) is bonded in a 5-coordinate geometry to one S(3), one S(4), one S(8), and two equivalent S(6) atoms. In the fourth Sm site, Sm(4) is bonded to one S(3), one S(4), one S(7), and two equivalent S(5) atoms to form distorted SmS5 trigonal bipyramids that share corners with two equivalent Sm(2)S6 octahedra, corners with three equivalent Mg(1)S4 tetrahedra, corners with two equivalent Sm(1)S5 trigonal bipyramids,  an edgeedge with one Sm(1)S5 trigonal bipyramid, and  an edgeedge with one Sm(4)S5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 60-62°. There are eight inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Mg(2), one Sm(1), and one Sm(2) atom to form SSm2Mg2 tetrahedra that share  a cornercorner with one S(3)Sm3Mg tetrahedra,  a cornercorner with one S(5)Sm3Mg tetrahedra,  a cornercorner with one S(6)Sm3Mg tetrahedra, corners with two equivalent S(2)Sm2Mg2 tetrahedra, corners with three equivalent S(8)Sm2Mg2 tetrahedra,  an edgeedge with one S(1)Sm2Mg2 tetrahedra,  an edgeedge with one S(2)Sm2Mg2 tetrahedra, and  an edgeedge with one S(8)Sm2Mg2 tetrahedra. In the second S site, S(2) is bonded to one Mg(1), one Mg(2), and two equivalent Sm(2) atoms to form SSm2Mg2 tetrahedra that share  a cornercorner with one S(3)Sm3Mg tetrahedra,  a cornercorner with one S(5)Sm3Mg tetrahedra,  a cornercorner with one S(6)Sm3Mg tetrahedra, corners with two equivalent S(1)Sm2Mg2 tetrahedra, corners with four equivalent S(8)Sm2Mg2 tetrahedra,  an edgeedge with one S(1)Sm2Mg2 tetrahedra, and  an edgeedge with one S(2)Sm2Mg2 tetrahedra. In the third S site, S(3) is bonded to one Mg(1), one Sm(1), one Sm(3), and one Sm(4) atom to form distorted SSm3Mg tetrahedra that share  a cornercorner with one S(1)Sm2Mg2 tetrahedra,  a cornercorner with one S(2)Sm2Mg2 tetrahedra,  a cornercorner with one S(8)Sm2Mg2 tetrahedra, corners with two equivalent S(5)Sm3Mg tetrahedra, corners with two equivalent S(6)Sm3Mg tetrahedra,  an edgeedge with one S(5)Sm3Mg tetrahedra, and  an edgeedge with one S(6)Sm3Mg tetrahedra. In the fourth S site, S(4) is bonded in a trigonal planar geometry to one Sm(1), one Sm(3), and one Sm(4) atom. In the fifth S site, S(5) is bonded to one Mg(1), one Sm(1), and two equivalent Sm(4) atoms to form distorted SSm3Mg tetrahedra that share  a cornercorner with one S(1)Sm2Mg2 tetrahedra,  a cornercorner with one S(2)Sm2Mg2 tetrahedra, corners with two equivalent S(3)Sm3Mg tetrahedra, corners with two equivalent S(6)Sm3Mg tetrahedra,  an edgeedge with one S(3)Sm3Mg tetrahedra, and  an edgeedge with one S(5)Sm3Mg tetrahedra. In the sixth S site, S(6) is bonded to one Mg(1), one Sm(1), and two equivalent Sm(3) atoms to form distorted SSm3Mg tetrahedra that share  a cornercorner with one S(1)Sm2Mg2 tetrahedra,  a cornercorner with one S(2)Sm2Mg2 tetrahedra, corners with two equivalent S(8)Sm2Mg2 tetrahedra, corners with two equivalent S(3)Sm3Mg tetrahedra, corners with two equivalent S(5)Sm3Mg tetrahedra,  an edgeedge with one S(3)Sm3Mg tetrahedra, and  an edgeedge with one S(6)Sm3Mg tetrahedra. In the seventh S site, S(7) is bonded in a 3-coordinate geometry to one Sm(4) and two equivalent Sm(2) atoms. In the eighth S site, S(8) is bonded to two equivalent Mg(2), one Sm(2), and one Sm(3) atom to form SSm2Mg2 tetrahedra that share  a cornercorner with one S(3)Sm3Mg tetrahedra, corners with two equivalent S(6)Sm3Mg tetrahedra, corners with three equivalent S(1)Sm2Mg2 tetrahedra, corners with four equivalent S(2)Sm2Mg2 tetrahedra,  an edgeedge with one S(1)Sm2Mg2 tetrahedra, and  an edgeedge with one S(8)Sm2Mg2 tetrahedra.
MgSm2S4 is Aluminum carbonitride-like structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one S(2), one S(3), one S(5), and one S(6) atom to form MgS4 tetrahedra that share corners with two equivalent Sm(2)S6 octahedra, corners with three equivalent Sm(1)S5 trigonal bipyramids, and corners with three equivalent Sm(4)S5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 66°. The Mg(1)-S(2) bond length is 2.40 Å. The Mg(1)-S(3) bond length is 2.48 Å. The Mg(1)-S(5) bond length is 2.51 Å. The Mg(1)-S(6) bond length is 2.48 Å. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one S(2), two equivalent S(1), and two equivalent S(8) atoms. The Mg(2)-S(2) bond length is 2.71 Å. There is one shorter (2.66 Å) and one longer (2.82 Å) Mg(2)-S(1) bond length. There is one shorter (2.70 Å) and one longer (2.76 Å) Mg(2)-S(8) bond length. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one S(1), one S(3), one S(4), one S(5), and one S(6) atom to form distorted SmS5 trigonal bipyramids that share  a cornercorner with one Sm(2)S6 octahedra, corners with three equivalent Mg(1)S4 tetrahedra, corners with two equivalent Sm(4)S5 trigonal bipyramids, and  an edgeedge with one Sm(4)S5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 65°. The Sm(1)-S(1) bond length is 2.65 Å. The Sm(1)-S(3) bond length is 3.06 Å. The Sm(1)-S(4) bond length is 2.62 Å. The Sm(1)-S(5) bond length is 2.72 Å. The Sm(1)-S(6) bond length is 2.69 Å. In the second Sm site, Sm(2) is bonded to one S(1), one S(8), two equivalent S(2), and two equivalent S(7) atoms to form SmS6 octahedra that share corners with two equivalent Mg(1)S4 tetrahedra,  a cornercorner with one Sm(1)S5 trigonal bipyramid, corners with two equivalent Sm(4)S5 trigonal bipyramids, and edges with two equivalent Sm(2)S6 octahedra. The Sm(2)-S(1) bond length is 2.86 Å. The Sm(2)-S(8) bond length is 2.91 Å. There is one shorter (2.87 Å) and one longer (2.91 Å) Sm(2)-S(2) bond length. Both Sm(2)-S(7) bond lengths are 2.83 Å. In the third Sm site, Sm(3) is bonded in a 5-coordinate geometry to one S(3), one S(4), one S(8), and two equivalent S(6) atoms. The Sm(3)-S(3) bond length is 2.69 Å. The Sm(3)-S(4) bond length is 2.62 Å. The Sm(3)-S(8) bond length is 2.65 Å. There is one shorter (2.67 Å) and one longer (3.13 Å) Sm(3)-S(6) bond length. In the fourth Sm site, Sm(4) is bonded to one S(3), one S(4), one S(7), and two equivalent S(5) atoms to form distorted SmS5 trigonal bipyramids that share corners with two equivalent Sm(2)S6 octahedra, corners with three equivalent Mg(1)S4 tetrahedra, corners with two equivalent Sm(1)S5 trigonal bipyramids,  an edgeedge with one Sm(1)S5 trigonal bipyramid, and  an edgeedge with one Sm(4)S5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 60-62°. The Sm(4)-S(3) bond length is 2.67 Å. The Sm(4)-S(4) bond length is 2.62 Å. The Sm(4)-S(7) bond length is 2.63 Å. There is one shorter (2.69 Å) and one longer (3.03 Å) Sm(4)-S(5) bond length. There are eight inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Mg(2), one Sm(1), and one Sm(2) atom to form SSm2Mg2 tetrahedra that share  a cornercorner with one S(3)Sm3Mg tetrahedra,  a cornercorner with one S(5)Sm3Mg tetrahedra,  a cornercorner with one S(6)Sm3Mg tetrahedra, corners with two equivalent S(2)Sm2Mg2 tetrahedra, corners with three equivalent S(8)Sm2Mg2 tetrahedra,  an edgeedge with one S(1)Sm2Mg2 tetrahedra,  an edgeedge with one S(2)Sm2Mg2 tetrahedra, and  an edgeedge with one S(8)Sm2Mg2 tetrahedra. In the second S site, S(2) is bonded to one Mg(1), one Mg(2), and two equivalent Sm(2) atoms to form SSm2Mg2 tetrahedra that share  a cornercorner with one S(3)Sm3Mg tetrahedra,  a cornercorner with one S(5)Sm3Mg tetrahedra,  a cornercorner with one S(6)Sm3Mg tetrahedra, corners with two equivalent S(1)Sm2Mg2 tetrahedra, corners with four equivalent S(8)Sm2Mg2 tetrahedra,  an edgeedge with one S(1)Sm2Mg2 tetrahedra, and  an edgeedge with one S(2)Sm2Mg2 tetrahedra. In the third S site, S(3) is bonded to one Mg(1), one Sm(1), one Sm(3), and one Sm(4) atom to form distorted SSm3Mg tetrahedra that share  a cornercorner with one S(1)Sm2Mg2 tetrahedra,  a cornercorner with one S(2)Sm2Mg2 tetrahedra,  a cornercorner with one S(8)Sm2Mg2 tetrahedra, corners with two equivalent S(5)Sm3Mg tetrahedra, corners with two equivalent S(6)Sm3Mg tetrahedra,  an edgeedge with one S(5)Sm3Mg tetrahedra, and  an edgeedge with one S(6)Sm3Mg tetrahedra. In the fourth S site, S(4) is bonded in a trigonal planar geometry to one Sm(1), one Sm(3), and one Sm(4) atom. In the fifth S site, S(5) is bonded to one Mg(1), one Sm(1), and two equivalent Sm(4) atoms to form distorted SSm3Mg tetrahedra that share  a cornercorner with one S(1)Sm2Mg2 tetrahedra,  a cornercorner with one S(2)Sm2Mg2 tetrahedra, corners with two equivalent S(3)Sm3Mg tetrahedra, corners with two equivalent S(6)Sm3Mg tetrahedra,  an edgeedge with one S(3)Sm3Mg tetrahedra, and  an edgeedge with one S(5)Sm3Mg tetrahedra. In the sixth S site, S(6) is bonded to one Mg(1), one Sm(1), and two equivalent Sm(3) atoms to form distorted SSm3Mg tetrahedra that share  a cornercorner with one S(1)Sm2Mg2 tetrahedra,  a cornercorner with one S(2)Sm2Mg2 tetrahedra, corners with two equivalent S(8)Sm2Mg2 tetrahedra, corners with two equivalent S(3)Sm3Mg tetrahedra, corners with two equivalent S(5)Sm3Mg tetrahedra,  an edgeedge with one S(3)Sm3Mg tetrahedra, and  an edgeedge with one S(6)Sm3Mg tetrahedra. In the seventh S site, S(7) is bonded in a 3-coordinate geometry to one Sm(4) and two equivalent Sm(2) atoms. In the eighth S site, S(8) is bonded to two equivalent Mg(2), one Sm(2), and one Sm(3) atom to form SSm2Mg2 tetrahedra that share  a cornercorner with one S(3)Sm3Mg tetrahedra, corners with two equivalent S(6)Sm3Mg tetrahedra, corners with three equivalent S(1)Sm2Mg2 tetrahedra, corners with four equivalent S(2)Sm2Mg2 tetrahedra,  an edgeedge with one S(1)Sm2Mg2 tetrahedra, and  an edgeedge with one S(8)Sm2Mg2 tetrahedra.