Yb2S3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Yb sites. In the first Yb site, Yb(1) is bonded to two equivalent S(1), three equivalent S(2), and three equivalent S(3) atoms to form distorted YbS8 hexagonal bipyramids that share corners with two equivalent Yb(1)S8 hexagonal bipyramids, corners with three equivalent S(3)Yb5S octahedra, edges with three equivalent Yb(1)S8 hexagonal bipyramids, and faces with two equivalent Yb(1)S8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 56-113°. In the second Yb site, Yb(2) is bonded in a 8-coordinate geometry to two equivalent S(1), two equivalent S(3), and four equivalent S(2) atoms. In the third Yb site, Yb(3) is bonded in a 8-coordinate geometry to two equivalent S(2), two equivalent S(3), and four equivalent S(1) atoms. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to one Yb(2), two equivalent Yb(1), two equivalent Yb(3), and one S(1) atom. In the second S site, S(2) is bonded to one Yb(3), two equivalent Yb(2), and three equivalent Yb(1) atoms to form SYb6 octahedra that share corners with three equivalent S(2)Yb6 octahedra, corners with seven equivalent S(3)Yb5S octahedra,  an edgeedge with one S(3)Yb5S octahedra, edges with two equivalent S(2)Yb6 octahedra, faces with two equivalent S(3)Yb5S octahedra, and faces with two equivalent S(2)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 10-66°. In the third S site, S(3) is bonded to one Yb(2), one Yb(3), three equivalent Yb(1), and one S(3) atom to form distorted SYb5S octahedra that share corners with three equivalent Yb(1)S8 hexagonal bipyramids, corners with five equivalent S(3)Yb5S octahedra, corners with seven equivalent S(2)Yb6 octahedra,  an edgeedge with one S(2)Yb6 octahedra,  a faceface with one S(3)Yb5S octahedra, and faces with two equivalent S(2)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 10-80°.
Yb2S3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Yb sites. In the first Yb site, Yb(1) is bonded to two equivalent S(1), three equivalent S(2), and three equivalent S(3) atoms to form distorted YbS8 hexagonal bipyramids that share corners with two equivalent Yb(1)S8 hexagonal bipyramids, corners with three equivalent S(3)Yb5S octahedra, edges with three equivalent Yb(1)S8 hexagonal bipyramids, and faces with two equivalent Yb(1)S8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 56-113°. There is one shorter (2.82 Å) and one longer (2.91 Å) Yb(1)-S(1) bond length. There are two shorter (2.78 Å) and one longer (2.84 Å) Yb(1)-S(2) bond length. There are a spread of Yb(1)-S(3) bond distances ranging from 2.81-3.25 Å. In the second Yb site, Yb(2) is bonded in a 8-coordinate geometry to two equivalent S(1), two equivalent S(3), and four equivalent S(2) atoms. Both Yb(2)-S(1) bond lengths are 2.97 Å. Both Yb(2)-S(3) bond lengths are 2.96 Å. There are two shorter (2.86 Å) and two longer (2.97 Å) Yb(2)-S(2) bond lengths. In the third Yb site, Yb(3) is bonded in a 8-coordinate geometry to two equivalent S(2), two equivalent S(3), and four equivalent S(1) atoms. Both Yb(3)-S(2) bond lengths are 2.79 Å. Both Yb(3)-S(3) bond lengths are 3.17 Å. There are two shorter (2.84 Å) and two longer (3.32 Å) Yb(3)-S(1) bond lengths. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to one Yb(2), two equivalent Yb(1), two equivalent Yb(3), and one S(1) atom. The S(1)-S(1) bond length is 2.13 Å. In the second S site, S(2) is bonded to one Yb(3), two equivalent Yb(2), and three equivalent Yb(1) atoms to form SYb6 octahedra that share corners with three equivalent S(2)Yb6 octahedra, corners with seven equivalent S(3)Yb5S octahedra,  an edgeedge with one S(3)Yb5S octahedra, edges with two equivalent S(2)Yb6 octahedra, faces with two equivalent S(3)Yb5S octahedra, and faces with two equivalent S(2)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 10-66°. In the third S site, S(3) is bonded to one Yb(2), one Yb(3), three equivalent Yb(1), and one S(3) atom to form distorted SYb5S octahedra that share corners with three equivalent Yb(1)S8 hexagonal bipyramids, corners with five equivalent S(3)Yb5S octahedra, corners with seven equivalent S(2)Yb6 octahedra,  an edgeedge with one S(2)Yb6 octahedra,  a faceface with one S(3)Yb5S octahedra, and faces with two equivalent S(2)Yb6 octahedra. The corner-sharing octahedral tilt angles range from 10-80°. The S(3)-S(3) bond length is 2.11 Å.