K5(TmI4)3 crystallizes in the hexagonal P-62m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to six equivalent I(3) atoms to form distorted KI6 pentagonal pyramids that share corners with six equivalent Tm(1)I6 octahedra and faces with two equivalent K(1)I6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 71°. In the second K site, K(2) is bonded in a 7-coordinate geometry to one I(2), two equivalent I(1), and four equivalent I(3) atoms. Tm(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form TmI6 octahedra that share corners with four equivalent K(1)I6 pentagonal pyramids and edges with two equivalent Tm(1)I6 octahedra. There are three inequivalent I sites. In the first I site, I(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(2) and two equivalent Tm(1) atoms. In the second I site, I(2) is bonded in a 3-coordinate geometry to one K(2) and two equivalent Tm(1) atoms. In the third I site, I(3) is bonded to two equivalent K(1), two equivalent K(2), and one Tm(1) atom to form a mixture of distorted edge and corner-sharing IK4Tm trigonal bipyramids.
K5(TmI4)3 crystallizes in the hexagonal P-62m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to six equivalent I(3) atoms to form distorted KI6 pentagonal pyramids that share corners with six equivalent Tm(1)I6 octahedra and faces with two equivalent K(1)I6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 71°. All K(1)-I(3) bond lengths are 3.65 Å. In the second K site, K(2) is bonded in a 7-coordinate geometry to one I(2), two equivalent I(1), and four equivalent I(3) atoms. The K(2)-I(2) bond length is 3.74 Å. Both K(2)-I(1) bond lengths are 3.66 Å. All K(2)-I(3) bond lengths are 3.55 Å. Tm(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form TmI6 octahedra that share corners with four equivalent K(1)I6 pentagonal pyramids and edges with two equivalent Tm(1)I6 octahedra. Both Tm(1)-I(1) bond lengths are 3.09 Å. Both Tm(1)-I(2) bond lengths are 3.05 Å. Both Tm(1)-I(3) bond lengths are 3.05 Å. There are three inequivalent I sites. In the first I site, I(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(2) and two equivalent Tm(1) atoms. In the second I site, I(2) is bonded in a 3-coordinate geometry to one K(2) and two equivalent Tm(1) atoms. In the third I site, I(3) is bonded to two equivalent K(1), two equivalent K(2), and one Tm(1) atom to form a mixture of distorted edge and corner-sharing IK4Tm trigonal bipyramids.