Materials Data on RbBa2Fe2F9 by Materials Project

Abstract

RbBa2Fe2F9 crystallizes in the trigonal R3m space group. The structure is three-dimensional. Rb1+ is bonded to twelve F1- atoms to form distorted RbF12 cuboctahedra that share corners with six equivalent RbF12 cuboctahedra, corners with three equivalent FeF6 octahedra, faces with four equivalent BaF12 cuboctahedra, and faces with four FeF6 octahedra. The corner-sharing octahedral tilt angles are 25°. There are a spread of Rb–F bond distances ranging from 2.85–3.13 Å. There are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve F1- atoms to form BaF12 cuboctahedra that share corners with six equivalent BaF12 cuboctahedra, faces with four equivalent RbF12 cuboctahedra, and faces with six FeF6 octahedra. There are a spread of Ba–F bond distances ranging from 2.78–3.00 Å. In the second Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve F1- atoms. There are a spread of Ba–F bond distances ranging from 2.68–3.13 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with three equivalent RbF12 cuboctahedra, corners with three equivalent FeF6 octahedra, a faceface with one RbF12 cuboctahedra, and faces with three equivalent BaF12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (2.04 Å) and three longer (2.14 Å) Fe–F bond lengths. In the second Fe2+ site, Fe2+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with three equivalent FeF6 octahedra, faces with three equivalent RbF12 cuboctahedra, and faces with three equivalent BaF12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (2.04 Å) and three longer (2.16 Å) Fe–F bond lengths. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to one Rb1+, three Ba2+, and one Fe2+ atom. In the second F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent Rb1+, two Ba2+, and one Fe2+ atom. In the third F1- site, F1- is bonded in a distorted linear geometry to one Rb1+, three Ba2+, and two Fe2+ atoms.