Materials Data on KAlNiF6 by Materials Project

Abstract

KNiAlF6 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. K1+ is bonded to six F1- atoms to form distorted KF6 octahedra that share corners with six equivalent NiF6 octahedra and corners with six equivalent AlF6 octahedra. The corner-sharing octahedra tilt angles range from 63–74°. There are a spread of K–F bond distances ranging from 2.82–3.34 Å. Ni2+ is bonded to six F1- atoms to form NiF6 octahedra that share corners with two equivalent NiF6 octahedra, corners with four equivalent AlF6 octahedra, and corners with six equivalent KF6 octahedra. The corner-sharing octahedra tilt angles range from 44–71°. There are two shorter (1.99 Å) and four longer (2.03 Å) Ni–F bond lengths. Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share corners with two equivalent AlF6 octahedra, corners with four equivalent NiF6 octahedra, and corners with six equivalent KF6 octahedra. The corner-sharing octahedra tilt angles range from 32–74°. There is four shorter (1.81 Å) and two longer (1.85 Å) Al–F bond length. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a bent 150 degrees geometry to one K1+ and two equivalent Al3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to one K1+ and two equivalent Ni2+ atoms. In the third F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Ni2+, and one Al3+ atom.