ErNd5S8 crystallizes in the tetragonal I-4 space group. Er(1) is bonded to four equivalent S(1) and four equivalent S(2) atoms to form distorted ErS8 hexagonal bipyramids that share corners with eight equivalent Nd(1)S8 hexagonal bipyramids, edges with four equivalent Nd(2)S8 hexagonal bipyramids, and faces with eight equivalent Nd(1)S8 hexagonal bipyramids. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to four equivalent S(1) and four equivalent S(2) atoms to form distorted NdS8 hexagonal bipyramids that share corners with two equivalent Er(1)S8 hexagonal bipyramids, corners with two equivalent Nd(2)S8 hexagonal bipyramids, corners with four equivalent Nd(1)S8 hexagonal bipyramids, edges with four equivalent Nd(1)S8 hexagonal bipyramids, faces with two equivalent Er(1)S8 hexagonal bipyramids, faces with two equivalent Nd(2)S8 hexagonal bipyramids, and faces with four equivalent Nd(1)S8 hexagonal bipyramids. In the second Nd site, Nd(2) is bonded to four equivalent S(1) and four equivalent S(2) atoms to form distorted NdS8 hexagonal bipyramids that share corners with eight equivalent Nd(1)S8 hexagonal bipyramids, edges with four equivalent Er(1)S8 hexagonal bipyramids, and faces with eight equivalent Nd(1)S8 hexagonal bipyramids. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Er(1), one Nd(2), and four equivalent Nd(1) atoms to form a mixture of distorted edge, face, and corner-sharing SNd5Er octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the second S site, S(2) is bonded to one Er(1), one Nd(2), and four equivalent Nd(1) atoms to form a mixture of distorted edge, face, and corner-sharing SNd5Er octahedra. The corner-sharing octahedral tilt angles range from 16-50°.
ErNd5S8 crystallizes in the tetragonal I-4 space group. Er(1) is bonded to four equivalent S(1) and four equivalent S(2) atoms to form distorted ErS8 hexagonal bipyramids that share corners with eight equivalent Nd(1)S8 hexagonal bipyramids, edges with four equivalent Nd(2)S8 hexagonal bipyramids, and faces with eight equivalent Nd(1)S8 hexagonal bipyramids. All Er(1)-S(1) bond lengths are 2.79 Å. All Er(1)-S(2) bond lengths are 3.02 Å. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to four equivalent S(1) and four equivalent S(2) atoms to form distorted NdS8 hexagonal bipyramids that share corners with two equivalent Er(1)S8 hexagonal bipyramids, corners with two equivalent Nd(2)S8 hexagonal bipyramids, corners with four equivalent Nd(1)S8 hexagonal bipyramids, edges with four equivalent Nd(1)S8 hexagonal bipyramids, faces with two equivalent Er(1)S8 hexagonal bipyramids, faces with two equivalent Nd(2)S8 hexagonal bipyramids, and faces with four equivalent Nd(1)S8 hexagonal bipyramids. There are a spread of Nd(1)-S(1) bond distances ranging from 2.88-3.12 Å. There are a spread of Nd(1)-S(2) bond distances ranging from 2.87-3.02 Å. In the second Nd site, Nd(2) is bonded to four equivalent S(1) and four equivalent S(2) atoms to form distorted NdS8 hexagonal bipyramids that share corners with eight equivalent Nd(1)S8 hexagonal bipyramids, edges with four equivalent Er(1)S8 hexagonal bipyramids, and faces with eight equivalent Nd(1)S8 hexagonal bipyramids. All Nd(2)-S(1) bond lengths are 3.06 Å. All Nd(2)-S(2) bond lengths are 2.89 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Er(1), one Nd(2), and four equivalent Nd(1) atoms to form a mixture of distorted edge, face, and corner-sharing SNd5Er octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the second S site, S(2) is bonded to one Er(1), one Nd(2), and four equivalent Nd(1) atoms to form a mixture of distorted edge, face, and corner-sharing SNd5Er octahedra. The corner-sharing octahedral tilt angles range from 16-50°.