MgNd2S4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded in a trigonal pyramidal geometry to one S(2), one S(3), and two equivalent S(1) atoms. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 7-coordinate geometry to one S(2), two equivalent S(3), and four equivalent S(1) atoms. In the second Nd site, Nd(2) is bonded in a 6-coordinate geometry to one S(2), one S(3), and four equivalent S(1) atoms. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), two equivalent Nd(1), and two equivalent Nd(2) atoms to form a mixture of distorted corner, edge, and face-sharing SNd4Mg square pyramids. In the second S site, S(2) is bonded in a T-shaped geometry to one Mg(1), one Nd(1), and one Nd(2) atom. In the third S site, S(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nd(2), and two equivalent Nd(1) atoms.
MgNd2S4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded in a trigonal pyramidal geometry to one S(2), one S(3), and two equivalent S(1) atoms. The Mg(1)-S(2) bond length is 2.33 Å. The Mg(1)-S(3) bond length is 2.42 Å. Both Mg(1)-S(1) bond lengths are 2.43 Å. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 7-coordinate geometry to one S(2), two equivalent S(3), and four equivalent S(1) atoms. The Nd(1)-S(2) bond length is 2.87 Å. There is one shorter (2.80 Å) and one longer (2.83 Å) Nd(1)-S(3) bond length. There are two shorter (2.95 Å) and two longer (3.24 Å) Nd(1)-S(1) bond lengths. In the second Nd site, Nd(2) is bonded in a 6-coordinate geometry to one S(2), one S(3), and four equivalent S(1) atoms. The Nd(2)-S(2) bond length is 2.69 Å. The Nd(2)-S(3) bond length is 2.94 Å. There are two shorter (2.88 Å) and two longer (2.98 Å) Nd(2)-S(1) bond lengths. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), two equivalent Nd(1), and two equivalent Nd(2) atoms to form a mixture of distorted corner, edge, and face-sharing SNd4Mg square pyramids. In the second S site, S(2) is bonded in a T-shaped geometry to one Mg(1), one Nd(1), and one Nd(2) atom. In the third S site, S(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nd(2), and two equivalent Nd(1) atoms.