Rb8Nd(AsS4)4 crystallizes in the orthorhombic I222 space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to two equivalent S(4) and four equivalent S(3) atoms. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to two equivalent S(2), two equivalent S(4), and four equivalent S(3) atoms. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to one S(3), one S(4), three equivalent S(1), and three equivalent S(2) atoms. Nd(1) is bonded to four equivalent S(1) and four equivalent S(4) atoms to form distorted NdS8 hexagonal bipyramids that share edges with four equivalent As(1)S4 tetrahedra. As(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form AsS4 tetrahedra that share  an edgeedge with one Nd(1)S8 hexagonal bipyramid. There are four inequivalent S sites. In the first S site, S(3) is bonded in a 6-coordinate geometry to one Rb(3), two equivalent Rb(1), two equivalent Rb(2), and one As(1) atom. In the second S site, S(4) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Nd(1), and one As(1) atom. In the third S site, S(1) is bonded in a 5-coordinate geometry to three equivalent Rb(3), one Nd(1), and one As(1) atom. In the fourth S site, S(2) is bonded in a 1-coordinate geometry to one Rb(2), three equivalent Rb(3), and one As(1) atom.
Rb8Nd(AsS4)4 crystallizes in the orthorhombic I222 space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to two equivalent S(4) and four equivalent S(3) atoms. Both Rb(1)-S(4) bond lengths are 3.50 Å. There are two shorter (3.42 Å) and two longer (3.57 Å) Rb(1)-S(3) bond lengths. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to two equivalent S(2), two equivalent S(4), and four equivalent S(3) atoms. Both Rb(2)-S(2) bond lengths are 3.85 Å. Both Rb(2)-S(4) bond lengths are 3.65 Å. There are two shorter (3.49 Å) and two longer (3.64 Å) Rb(2)-S(3) bond lengths. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to one S(3), one S(4), three equivalent S(1), and three equivalent S(2) atoms. The Rb(3)-S(3) bond length is 3.78 Å. The Rb(3)-S(4) bond length is 3.22 Å. There are a spread of Rb(3)-S(1) bond distances ranging from 3.51-3.79 Å. There are a spread of Rb(3)-S(2) bond distances ranging from 3.45-3.54 Å. Nd(1) is bonded to four equivalent S(1) and four equivalent S(4) atoms to form distorted NdS8 hexagonal bipyramids that share edges with four equivalent As(1)S4 tetrahedra. All Nd(1)-S(1) bond lengths are 3.04 Å. All Nd(1)-S(4) bond lengths are 3.00 Å. As(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form AsS4 tetrahedra that share  an edgeedge with one Nd(1)S8 hexagonal bipyramid. The As(1)-S(1) bond length is 2.18 Å. The As(1)-S(2) bond length is 2.19 Å. The As(1)-S(3) bond length is 2.18 Å. The As(1)-S(4) bond length is 2.20 Å. There are four inequivalent S sites. In the first S site, S(3) is bonded in a 6-coordinate geometry to one Rb(3), two equivalent Rb(1), two equivalent Rb(2), and one As(1) atom. In the second S site, S(4) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Nd(1), and one As(1) atom. In the third S site, S(1) is bonded in a 5-coordinate geometry to three equivalent Rb(3), one Nd(1), and one As(1) atom. In the fourth S site, S(2) is bonded in a 1-coordinate geometry to one Rb(2), three equivalent Rb(3), and one As(1) atom.