Materials Data on Cs3Er2Br9 by Materials Project
Cs3Er2Br9 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Cs1+ is bonded to twelve Br1- atoms to form CsBr12 cuboctahedra that share corners with six equivalent CsBr12 cuboctahedra, corners with four equivalent ErBr6 octahedra, faces with eight equivalent CsBr12 cuboctahedra, and faces with four equivalent ErBr6 octahedra. The corner-sharing octahedra tilt angles range from 12–29°. There are a spread of Cs–Br bond distances ranging from 3.95–4.17 Å. Er3+ is bonded to six Br1- atoms to form ErBr6 octahedra that share corners with six equivalent CsBr12 cuboctahedra, faces with six equivalent CsBr12 cuboctahedra, and a faceface with one ErBr6 octahedra. There are three shorter (2.69 Å) and three longer (2.89 Å) Er–Br bond lengths. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted single-bond geometry to four equivalent Cs1+ and one Er3+ atom. In the second Br1- site, Br1- is bonded in a distorted L-shaped geometry to four equivalent Cs1+ and two equivalent Er3+ atoms.