KEuAsS3 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 7-coordinate geometry to one S(2), three equivalent S(1), and three equivalent S(3) atoms. Eu(1) is bonded in a 7-coordinate geometry to one S(1), two equivalent S(3), and four equivalent S(2) atoms. As(1) is bonded in a distorted trigonal non-coplanar geometry to one S(1), one S(2), and one S(3) atom. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to three equivalent K(1), one Eu(1), and one As(1) atom. In the second S site, S(2) is bonded to one K(1), four equivalent Eu(1), and one As(1) atom to form distorted SKEu4As octahedra that share corners with four equivalent S(3)K3Eu2As octahedra, corners with four equivalent S(2)KEu4As octahedra,  an edgeedge with one S(3)K3Eu2As octahedra, edges with four equivalent S(2)KEu4As octahedra, and faces with two equivalent S(3)K3Eu2As octahedra. The corner-sharing octahedral tilt angles range from 22-73°. In the third S site, S(3) is bonded to three equivalent K(1), two equivalent Eu(1), and one As(1) atom to form distorted SK3Eu2As octahedra that share corners with four equivalent S(3)K3Eu2As octahedra, corners with four equivalent S(2)KEu4As octahedra,  an edgeedge with one S(2)KEu4As octahedra, edges with two equivalent S(3)K3Eu2As octahedra, and faces with two equivalent S(2)KEu4As octahedra. The corner-sharing octahedral tilt angles range from 35-81°.
KEuAsS3 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 7-coordinate geometry to one S(2), three equivalent S(1), and three equivalent S(3) atoms. The K(1)-S(2) bond length is 3.35 Å. There are a spread of K(1)-S(1) bond distances ranging from 3.33-3.60 Å. There are a spread of K(1)-S(3) bond distances ranging from 3.27-3.50 Å. Eu(1) is bonded in a 7-coordinate geometry to one S(1), two equivalent S(3), and four equivalent S(2) atoms. The Eu(1)-S(1) bond length is 2.94 Å. There is one shorter (3.01 Å) and one longer (3.02 Å) Eu(1)-S(3) bond length. There are a spread of Eu(1)-S(2) bond distances ranging from 3.06-3.32 Å. As(1) is bonded in a distorted trigonal non-coplanar geometry to one S(1), one S(2), and one S(3) atom. The As(1)-S(1) bond length is 2.25 Å. The As(1)-S(2) bond length is 2.32 Å. The As(1)-S(3) bond length is 2.27 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to three equivalent K(1), one Eu(1), and one As(1) atom. In the second S site, S(2) is bonded to one K(1), four equivalent Eu(1), and one As(1) atom to form distorted SKEu4As octahedra that share corners with four equivalent S(3)K3Eu2As octahedra, corners with four equivalent S(2)KEu4As octahedra,  an edgeedge with one S(3)K3Eu2As octahedra, edges with four equivalent S(2)KEu4As octahedra, and faces with two equivalent S(3)K3Eu2As octahedra. The corner-sharing octahedral tilt angles range from 22-73°. In the third S site, S(3) is bonded to three equivalent K(1), two equivalent Eu(1), and one As(1) atom to form distorted SK3Eu2As octahedra that share corners with four equivalent S(3)K3Eu2As octahedra, corners with four equivalent S(2)KEu4As octahedra,  an edgeedge with one S(2)KEu4As octahedra, edges with two equivalent S(3)K3Eu2As octahedra, and faces with two equivalent S(2)KEu4As octahedra. The corner-sharing octahedral tilt angles range from 35-81°.