Yb4SmS5 is Caswellsilverite-like structured and crystallizes in the orthorhombic Immm space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form YbS6 octahedra that share corners with two equivalent Yb(2)S6 octahedra, corners with four equivalent Yb(1)S6 octahedra, edges with three equivalent Yb(1)S6 octahedra, edges with four equivalent Sm(1)S6 octahedra, and edges with five equivalent Yb(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Yb site, Yb(2) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form YbS6 octahedra that share corners with two equivalent Yb(1)S6 octahedra, corners with two equivalent Yb(2)S6 octahedra, corners with two equivalent Sm(1)S6 octahedra,  an edgeedge with one Sm(1)S6 octahedra, edges with five equivalent Yb(1)S6 octahedra, and edges with six equivalent Yb(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Sm(1) is bonded to two equivalent S(3) and four equivalent S(2) atoms to form SmS6 octahedra that share corners with two equivalent Sm(1)S6 octahedra, corners with four equivalent Yb(2)S6 octahedra, edges with two equivalent Yb(2)S6 octahedra, edges with two equivalent Sm(1)S6 octahedra, and edges with eight equivalent Yb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. There are three inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Yb(1) and four equivalent Yb(2) atoms to form SYb6 octahedra that share corners with two equivalent S(2)Yb4Sm2 octahedra, corners with two equivalent S(3)Yb4Sm2 octahedra, corners with two equivalent S(1)Yb6 octahedra,  an edgeedge with one S(3)Yb4Sm2 octahedra, edges with five equivalent S(2)Yb4Sm2 octahedra, and edges with six equivalent S(1)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second S site, S(2) is bonded to two equivalent Yb(1), two equivalent Yb(2), and two equivalent Sm(1) atoms to form SYb4Sm2 octahedra that share corners with two equivalent S(1)Yb6 octahedra, corners with four equivalent S(2)Yb4Sm2 octahedra, edges with three equivalent S(2)Yb4Sm2 octahedra, edges with four equivalent S(3)Yb4Sm2 octahedra, and edges with five equivalent S(1)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third S site, S(3) is bonded to four equivalent Yb(1) and two equivalent Sm(1) atoms to form SYb4Sm2 octahedra that share corners with two equivalent S(3)Yb4Sm2 octahedra, corners with four equivalent S(1)Yb6 octahedra, edges with two equivalent S(3)Yb4Sm2 octahedra, edges with two equivalent S(1)Yb6 octahedra, and edges with eight equivalent S(2)Yb4Sm2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.
Yb4SmS5 is Caswellsilverite-like structured and crystallizes in the orthorhombic Immm space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form YbS6 octahedra that share corners with two equivalent Yb(2)S6 octahedra, corners with four equivalent Yb(1)S6 octahedra, edges with three equivalent Yb(1)S6 octahedra, edges with four equivalent Sm(1)S6 octahedra, and edges with five equivalent Yb(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Both Yb(1)-S(1) bond lengths are 2.78 Å. Both Yb(1)-S(2) bond lengths are 2.80 Å. Both Yb(1)-S(3) bond lengths are 2.82 Å. In the second Yb site, Yb(2) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form YbS6 octahedra that share corners with two equivalent Yb(1)S6 octahedra, corners with two equivalent Yb(2)S6 octahedra, corners with two equivalent Sm(1)S6 octahedra,  an edgeedge with one Sm(1)S6 octahedra, edges with five equivalent Yb(1)S6 octahedra, and edges with six equivalent Yb(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Both Yb(2)-S(2) bond lengths are 2.79 Å. There are two shorter (2.79 Å) and two longer (2.80 Å) Yb(2)-S(1) bond lengths. Sm(1) is bonded to two equivalent S(3) and four equivalent S(2) atoms to form SmS6 octahedra that share corners with two equivalent Sm(1)S6 octahedra, corners with four equivalent Yb(2)S6 octahedra, edges with two equivalent Yb(2)S6 octahedra, edges with two equivalent Sm(1)S6 octahedra, and edges with eight equivalent Yb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Both Sm(1)-S(3) bond lengths are 2.80 Å. All Sm(1)-S(2) bond lengths are 2.83 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Yb(1) and four equivalent Yb(2) atoms to form SYb6 octahedra that share corners with two equivalent S(2)Yb4Sm2 octahedra, corners with two equivalent S(3)Yb4Sm2 octahedra, corners with two equivalent S(1)Yb6 octahedra,  an edgeedge with one S(3)Yb4Sm2 octahedra, edges with five equivalent S(2)Yb4Sm2 octahedra, and edges with six equivalent S(1)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second S site, S(2) is bonded to two equivalent Yb(1), two equivalent Yb(2), and two equivalent Sm(1) atoms to form SYb4Sm2 octahedra that share corners with two equivalent S(1)Yb6 octahedra, corners with four equivalent S(2)Yb4Sm2 octahedra, edges with three equivalent S(2)Yb4Sm2 octahedra, edges with four equivalent S(3)Yb4Sm2 octahedra, and edges with five equivalent S(1)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third S site, S(3) is bonded to four equivalent Yb(1) and two equivalent Sm(1) atoms to form SYb4Sm2 octahedra that share corners with two equivalent S(3)Yb4Sm2 octahedra, corners with four equivalent S(1)Yb6 octahedra, edges with two equivalent S(3)Yb4Sm2 octahedra, edges with two equivalent S(1)Yb6 octahedra, and edges with eight equivalent S(2)Yb4Sm2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.