Materials Data on K2Zr7Cl18 by Materials Project
K2Zr7Cl18 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. K1+ is bonded to twelve Cl1- atoms to form KCl12 cuboctahedra that share corners with three equivalent ZrCl6 octahedra, corners with six equivalent ZrCl5 square pyramids, edges with three equivalent KCl12 cuboctahedra, edges with three equivalent ZrCl5 square pyramids, and faces with three equivalent ZrCl5 square pyramids. The corner-sharing octahedral tilt angles are 47°. There are a spread of K–Cl bond distances ranging from 3.57–3.78 Å. There are two inequivalent Zr+2.29+ sites. In the first Zr+2.29+ site, Zr+2.29+ is bonded to six equivalent Cl1- atoms to form ZrCl6 octahedra that share corners with six equivalent KCl12 cuboctahedra and corners with six equivalent ZrCl5 square pyramids. All Zr–Cl bond lengths are 2.52 Å. In the second Zr+2.29+ site, Zr+2.29+ is bonded to five Cl1- atoms to form ZrCl5 square pyramids that share corners with two equivalent KCl12 cuboctahedra, a cornercorner with one ZrCl6 octahedra, corners with four equivalent ZrCl5 square pyramids, an edgeedge with one KCl12 cuboctahedra, and a faceface with one KCl12 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. There are a spread of Zr–Cl bond distances ranging from 2.56–2.82 Å. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one K1+ and two equivalent Zr+2.29+ atoms. In the second Cl1- site, Cl1- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Zr+2.29+ atoms. In the third Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one K1+ and two Zr+2.29+ atoms.