KSn3As3 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 8-coordinate geometry to two equivalent Sn(3), one As(3), two equivalent As(2), and three equivalent As(1) atoms. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one As(2), one As(3), and two equivalent As(1) atoms to form corner-sharing SnAs4 tetrahedra. In the second Sn site, Sn(2) is bonded in a 4-coordinate geometry to one Sn(3), one As(1), and two equivalent As(3) atoms. In the third Sn site, Sn(3) is bonded in a 5-coordinate geometry to two equivalent K(1), one Sn(2), and two equivalent As(2) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded to three equivalent K(1), one Sn(2), and two equivalent Sn(1) atoms to form AsK3Sn3 octahedra that share corners with two equivalent As(2)K2Sn3 square pyramids, edges with four equivalent As(1)K3Sn3 octahedra, and edges with three equivalent As(2)K2Sn3 square pyramids. In the second As site, As(2) is bonded to two equivalent K(1), one Sn(1), and two equivalent Sn(3) atoms to form AsK2Sn3 square pyramids that share corners with two equivalent As(1)K3Sn3 octahedra, edges with three equivalent As(1)K3Sn3 octahedra, and edges with two equivalent As(2)K2Sn3 square pyramids. The corner-sharing octahedral tilt angles are 16°. In the third As site, As(3) is bonded in a rectangular see-saw-like geometry to one K(1), one Sn(1), and two equivalent Sn(2) atoms.
KSn3As3 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 8-coordinate geometry to two equivalent Sn(3), one As(3), two equivalent As(2), and three equivalent As(1) atoms. Both K(1)-Sn(3) bond lengths are 3.82 Å. The K(1)-As(3) bond length is 3.54 Å. Both K(1)-As(2) bond lengths are 3.42 Å. There are two shorter (3.54 Å) and one longer (3.80 Å) K(1)-As(1) bond length. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one As(2), one As(3), and two equivalent As(1) atoms to form corner-sharing SnAs4 tetrahedra. The Sn(1)-As(2) bond length is 2.64 Å. The Sn(1)-As(3) bond length is 2.66 Å. Both Sn(1)-As(1) bond lengths are 2.70 Å. In the second Sn site, Sn(2) is bonded in a 4-coordinate geometry to one Sn(3), one As(1), and two equivalent As(3) atoms. The Sn(2)-Sn(3) bond length is 2.99 Å. The Sn(2)-As(1) bond length is 2.71 Å. Both Sn(2)-As(3) bond lengths are 2.73 Å. In the third Sn site, Sn(3) is bonded in a 5-coordinate geometry to two equivalent K(1), one Sn(2), and two equivalent As(2) atoms. Both Sn(3)-As(2) bond lengths are 2.77 Å. There are three inequivalent As sites. In the first As site, As(1) is bonded to three equivalent K(1), one Sn(2), and two equivalent Sn(1) atoms to form AsK3Sn3 octahedra that share corners with two equivalent As(2)K2Sn3 square pyramids, edges with four equivalent As(1)K3Sn3 octahedra, and edges with three equivalent As(2)K2Sn3 square pyramids. In the second As site, As(2) is bonded to two equivalent K(1), one Sn(1), and two equivalent Sn(3) atoms to form AsK2Sn3 square pyramids that share corners with two equivalent As(1)K3Sn3 octahedra, edges with three equivalent As(1)K3Sn3 octahedra, and edges with two equivalent As(2)K2Sn3 square pyramids. The corner-sharing octahedral tilt angles are 16°. In the third As site, As(3) is bonded in a rectangular see-saw-like geometry to one K(1), one Sn(1), and two equivalent Sn(2) atoms.