K2CuCl3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to two equivalent Cl(1), two equivalent Cl(3), and three equivalent Cl(2) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to two equivalent Cl(1), two equivalent Cl(2), and three equivalent Cl(3) atoms. Cu(1) is bonded to one Cl(2), one Cl(3), and two equivalent Cl(1) atoms to form corner-sharing CuCl4 tetrahedra. There are three inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent Cu(1) atoms to form distorted ClK4Cu2 octahedra that share corners with two equivalent Cl(1)K4Cu2 octahedra, corners with two equivalent Cl(2)K5Cu octahedra, corners with five equivalent Cl(3)K5Cu octahedra, edges with two equivalent Cl(1)K4Cu2 octahedra, edges with two equivalent Cl(3)K5Cu octahedra, edges with five equivalent Cl(2)K5Cu octahedra, and  a faceface with one Cl(3)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 16-61°. In the second Cl site, Cl(2) is bonded to two equivalent K(2), three equivalent K(1), and one Cu(1) atom to form distorted ClK5Cu octahedra that share corners with two equivalent Cl(1)K4Cu2 octahedra, corners with eight equivalent Cl(3)K5Cu octahedra,  an edgeedge with one Cl(3)K5Cu octahedra, edges with four equivalent Cl(2)K5Cu octahedra, edges with five equivalent Cl(1)K4Cu2 octahedra, and  a faceface with one Cl(3)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 16-57°. In the third Cl site, Cl(3) is bonded to two equivalent K(1), three equivalent K(2), and one Cu(1) atom to form distorted ClK5Cu octahedra that share corners with five equivalent Cl(1)K4Cu2 octahedra, corners with eight equivalent Cl(2)K5Cu octahedra,  an edgeedge with one Cl(2)K5Cu octahedra, edges with two equivalent Cl(1)K4Cu2 octahedra, edges with four equivalent Cl(3)K5Cu octahedra,  a faceface with one Cl(1)K4Cu2 octahedra, and  a faceface with one Cl(2)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 26-61°.
K2CuCl3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to two equivalent Cl(1), two equivalent Cl(3), and three equivalent Cl(2) atoms. Both K(1)-Cl(1) bond lengths are 3.22 Å. Both K(1)-Cl(3) bond lengths are 3.20 Å. There are two shorter (3.16 Å) and one longer (3.19 Å) K(1)-Cl(2) bond length. In the second K site, K(2) is bonded in a 7-coordinate geometry to two equivalent Cl(1), two equivalent Cl(2), and three equivalent Cl(3) atoms. There is one shorter (3.17 Å) and one longer (3.19 Å) K(2)-Cl(1) bond length. Both K(2)-Cl(2) bond lengths are 3.15 Å. There are two shorter (3.11 Å) and one longer (3.21 Å) K(2)-Cl(3) bond length. Cu(1) is bonded to one Cl(2), one Cl(3), and two equivalent Cl(1) atoms to form corner-sharing CuCl4 tetrahedra. The Cu(1)-Cl(2) bond length is 2.33 Å. The Cu(1)-Cl(3) bond length is 2.32 Å. Both Cu(1)-Cl(1) bond lengths are 2.37 Å. There are three inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent Cu(1) atoms to form distorted ClK4Cu2 octahedra that share corners with two equivalent Cl(1)K4Cu2 octahedra, corners with two equivalent Cl(2)K5Cu octahedra, corners with five equivalent Cl(3)K5Cu octahedra, edges with two equivalent Cl(1)K4Cu2 octahedra, edges with two equivalent Cl(3)K5Cu octahedra, edges with five equivalent Cl(2)K5Cu octahedra, and  a faceface with one Cl(3)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 16-61°. In the second Cl site, Cl(2) is bonded to two equivalent K(2), three equivalent K(1), and one Cu(1) atom to form distorted ClK5Cu octahedra that share corners with two equivalent Cl(1)K4Cu2 octahedra, corners with eight equivalent Cl(3)K5Cu octahedra,  an edgeedge with one Cl(3)K5Cu octahedra, edges with four equivalent Cl(2)K5Cu octahedra, edges with five equivalent Cl(1)K4Cu2 octahedra, and  a faceface with one Cl(3)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 16-57°. In the third Cl site, Cl(3) is bonded to two equivalent K(1), three equivalent K(2), and one Cu(1) atom to form distorted ClK5Cu octahedra that share corners with five equivalent Cl(1)K4Cu2 octahedra, corners with eight equivalent Cl(2)K5Cu octahedra,  an edgeedge with one Cl(2)K5Cu octahedra, edges with two equivalent Cl(1)K4Cu2 octahedra, edges with four equivalent Cl(3)K5Cu octahedra,  a faceface with one Cl(1)K4Cu2 octahedra, and  a faceface with one Cl(2)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 26-61°.