SmPr2S4 crystallizes in the tetragonal I-42d space group. Sm(1) is bonded to eight equivalent S(1) atoms to form distorted SmS8 hexagonal bipyramids that share corners with eight equivalent Pr(1)S8 hexagonal bipyramids, edges with four equivalent Sm(1)S8 hexagonal bipyramids, and faces with eight equivalent Pr(1)S8 hexagonal bipyramids. Pr(1) is bonded to eight equivalent S(1) atoms to form distorted PrS8 hexagonal bipyramids that share corners with four equivalent Sm(1)S8 hexagonal bipyramids, corners with four equivalent Pr(1)S8 hexagonal bipyramids, edges with four equivalent Pr(1)S8 hexagonal bipyramids, faces with four equivalent Sm(1)S8 hexagonal bipyramids, and faces with four equivalent Pr(1)S8 hexagonal bipyramids. S(1) is bonded to two equivalent Sm(1) and four equivalent Pr(1) atoms to form a mixture of distorted corner, face, and edge-sharing SPr4Sm2 octahedra. The corner-sharing octahedral tilt angles range from 17-50°.
SmPr2S4 crystallizes in the tetragonal I-42d space group. Sm(1) is bonded to eight equivalent S(1) atoms to form distorted SmS8 hexagonal bipyramids that share corners with eight equivalent Pr(1)S8 hexagonal bipyramids, edges with four equivalent Sm(1)S8 hexagonal bipyramids, and faces with eight equivalent Pr(1)S8 hexagonal bipyramids. There are four shorter (2.87 Å) and four longer (3.05 Å) Sm(1)-S(1) bond lengths. Pr(1) is bonded to eight equivalent S(1) atoms to form distorted PrS8 hexagonal bipyramids that share corners with four equivalent Sm(1)S8 hexagonal bipyramids, corners with four equivalent Pr(1)S8 hexagonal bipyramids, edges with four equivalent Pr(1)S8 hexagonal bipyramids, faces with four equivalent Sm(1)S8 hexagonal bipyramids, and faces with four equivalent Pr(1)S8 hexagonal bipyramids. There are a spread of Pr(1)-S(1) bond distances ranging from 2.89-3.07 Å. S(1) is bonded to two equivalent Sm(1) and four equivalent Pr(1) atoms to form a mixture of distorted corner, face, and edge-sharing SPr4Sm2 octahedra. The corner-sharing octahedral tilt angles range from 17-50°.