Materials Data on CaAs2F12 by Materials Project

Abstract

Ca(AsF6)2 crystallizes in the tetragonal P-4m2 space group. The structure is two-dimensional and consists of one Ca(AsF6)2 sheet oriented in the (0, 0, 1) direction. Ca2+ is bonded to twelve F1- atoms to form CaF12 cuboctahedra that share corners with four equivalent CaF12 cuboctahedra and faces with four equivalent AsF6 octahedra. There are eight shorter (2.64 Å) and four longer (2.69 Å) Ca–F bond lengths. As5+ is bonded to six F1- atoms to form AsF6 octahedra that share faces with two equivalent CaF12 cuboctahedra. There are a spread of As–F bond distances ranging from 1.72–1.83 Å. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ and one As5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to two equivalent Ca2+ and one As5+ atom.