Materials Data on K5(TmI4)3 by Materials Project
K5(TmI4)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to six equivalent I atoms to form distorted KI6 pentagonal pyramids that share corners with six equivalent TmI6 octahedra and faces with two equivalent KI6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 71°. All K–I bond lengths are 3.65 Å. In the second K site, K is bonded in a 7-coordinate geometry to seven I atoms. There are a spread of K–I bond distances ranging from 3.55–3.74 Å. Tm is bonded to six I atoms to form TmI6 octahedra that share corners with four equivalent KI6 pentagonal pyramids and edges with two equivalent TmI6 octahedra. There are four shorter (3.05 Å) and two longer (3.09 Å) Tm–I bond lengths. There are three inequivalent I sites. In the first I site, I is bonded in a distorted rectangular see-saw-like geometry to two equivalent K and two equivalent Tm atoms. In the second I site, I is bonded in a 3-coordinate geometry to one K and two equivalent Tm atoms. In the third I site, I is bonded to four K and one Tm atom to form a mixture of distorted corner and edge-sharing IK4Tm trigonal bipyramids.