Materials Data on CsEr(NbBr3)6 by Materials Project

Abstract

CsErNb6Br18 crystallizes in the trigonal P-31c space group. The structure is three-dimensional. Cs1+ is bonded in a 12-coordinate geometry to twelve Br1- atoms. There are six shorter (4.07 Å) and six longer (4.18 Å) Cs–Br bond lengths. Er3+ is bonded to six equivalent Br1- atoms to form ErBr6 octahedra that share corners with six equivalent NbBr5 square pyramids. All Er–Br bond lengths are 2.83 Å. Nb+2.33+ is bonded to five Br1- atoms to form distorted NbBr5 square pyramids that share a cornercorner with one ErBr6 octahedra and corners with four equivalent NbBr5 square pyramids. The corner-sharing octahedral tilt angles are 45°. There are a spread of Nb–Br bond distances ranging from 2.60–3.01 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 2-coordinate geometry to two equivalent Nb+2.33+ atoms. In the second Br1- site, Br1- is bonded in a 2-coordinate geometry to one Cs1+ and two equivalent Nb+2.33+ atoms. In the third Br1- site, Br1- is bonded in a 2-coordinate geometry to one Cs1+, one Er3+, and one Nb+2.33+ atom.