EuYb2S4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 6-coordinate geometry to one S(2), one S(3), two equivalent S(1), and three equivalent S(4) atoms. In the second Yb site, Yb(2) is bonded to one S(1), two equivalent S(3), and three equivalent S(2) atoms to form edge-sharing YbS6 octahedra. Eu(1) is bonded in a 8-coordinate geometry to two equivalent S(1), two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Yb(2), two equivalent Yb(1), and two equivalent Eu(1) atoms to form distorted edge-sharing SYb3Eu2 square pyramids. In the second S site, S(2) is bonded in a 7-coordinate geometry to one Yb(1), three equivalent Yb(2), two equivalent Eu(1), and one S(4) atom. In the third S site, S(3) is bonded to one Yb(1), two equivalent Yb(2), and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SYb3Eu2 trigonal bipyramids. In the fourth S site, S(4) is bonded in a 6-coordinate geometry to three equivalent Yb(1), two equivalent Eu(1), and one S(2) atom.
EuYb2S4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 6-coordinate geometry to one S(2), one S(3), two equivalent S(1), and three equivalent S(4) atoms. The Yb(1)-S(2) bond length is 3.44 Å. The Yb(1)-S(3) bond length is 2.83 Å. Both Yb(1)-S(1) bond lengths are 2.72 Å. There is one shorter (2.93 Å) and two longer (3.07 Å) Yb(1)-S(4) bond lengths. In the second Yb site, Yb(2) is bonded to one S(1), two equivalent S(3), and three equivalent S(2) atoms to form edge-sharing YbS6 octahedra. The Yb(2)-S(1) bond length is 2.65 Å. Both Yb(2)-S(3) bond lengths are 2.69 Å. There are two shorter (3.13 Å) and one longer (3.33 Å) Yb(2)-S(2) bond length. Eu(1) is bonded in a 8-coordinate geometry to two equivalent S(1), two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms. Both Eu(1)-S(1) bond lengths are 2.98 Å. Both Eu(1)-S(2) bond lengths are 3.20 Å. There is one shorter (2.95 Å) and one longer (3.04 Å) Eu(1)-S(3) bond length. Both Eu(1)-S(4) bond lengths are 3.08 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Yb(2), two equivalent Yb(1), and two equivalent Eu(1) atoms to form distorted edge-sharing SYb3Eu2 square pyramids. In the second S site, S(2) is bonded in a 7-coordinate geometry to one Yb(1), three equivalent Yb(2), two equivalent Eu(1), and one S(4) atom. The S(2)-S(4) bond length is 2.20 Å. In the third S site, S(3) is bonded to one Yb(1), two equivalent Yb(2), and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SYb3Eu2 trigonal bipyramids. In the fourth S site, S(4) is bonded in a 6-coordinate geometry to three equivalent Yb(1), two equivalent Eu(1), and one S(2) atom.