Materials Data on CsBa2Co2F9 by Materials Project
CsBa2Co2F9 crystallizes in the trigonal R3m space group. The structure is three-dimensional. Cs1+ is bonded to twelve F1- atoms to form distorted CsF12 cuboctahedra that share corners with six equivalent CsF12 cuboctahedra, corners with three equivalent CoF6 octahedra, faces with four equivalent BaF12 cuboctahedra, and faces with four CoF6 octahedra. The corner-sharing octahedral tilt angles are 26°. There are a spread of Cs–F bond distances ranging from 2.98–3.18 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 CsF12 cuboctahedra, and faces with six CoF6 octahedra. There are a spread of Ba–F bond distances ranging from 2.78–3.01 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 2.77–3.13 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six F1- atoms to form CoF6 octahedra that share corners with three equivalent CsF12 cuboctahedra, corners with three equivalent CoF6 octahedra, a faceface with one CsF12 cuboctahedra, and faces with three equivalent BaF12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (2.00 Å) and three longer (2.14 Å) Co–F bond lengths. In the second Co2+ site, Co2+ is bonded to six F1- atoms to form CoF6 octahedra that share corners with three equivalent CoF6 octahedra, faces with three equivalent CsF12 cuboctahedra, and faces with three equivalent BaF12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (2.02 Å) and three longer (2.15 Å) Co–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 Cs1+, three Ba2+, and one Co2+ atom. In the second F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent Cs1+, two Ba2+, and one Co2+ atom. In the third F1- site, F1- is bonded in a distorted linear geometry to one Cs1+, three Ba2+, and two Co2+ atoms.