Materials Data on K2Sr(NbCl3)6 by Materials Project

Abstract

K2Sr(NbCl3)6 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. K1+ is bonded to twelve Cl1- atoms to form distorted KCl12 cuboctahedra that share corners with three equivalent SrCl6 octahedra, corners with six equivalent NbCl5 square pyramids, edges with three equivalent KCl12 cuboctahedra, edges with three equivalent NbCl5 square pyramids, and faces with three equivalent NbCl5 square pyramids. The corner-sharing octahedral tilt angles are 52°. There are a spread of K–Cl bond distances ranging from 3.36–3.74 Å. Sr2+ is bonded to six equivalent Cl1- atoms to form SrCl6 octahedra that share corners with six equivalent KCl12 cuboctahedra and corners with six equivalent NbCl5 square pyramids. All Sr–Cl bond lengths are 2.98 Å. Nb+2.33+ is bonded to five Cl1- atoms to form NbCl5 square pyramids that share corners with two equivalent KCl12 cuboctahedra, a cornercorner with one SrCl6 octahedra, corners with four equivalent NbCl5 square pyramids, an edgeedge with one KCl12 cuboctahedra, and a faceface with one KCl12 cuboctahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Nb–Cl bond distances ranging from 2.47–2.66 Å. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 3-coordinate geometry to one K1+, one Sr2+, and one Nb+2.33+ atom. In the second Cl1- site, Cl1- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Nb+2.33+ atoms. In the third Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one K1+ and two equivalent Nb+2.33+ atoms.