Synthesis and crystal structure of RbKLiAlF6 - The first al-elpasolite with three different alkali metals

Abstract

The synthesis of RbKLiAlF6 via a sol-gel route is described. The crystal structure has been determined using Rietveld-refinement. It is shown that the compound crystallizes in the hexagonal 12L-structure of the Cs 2NaCrF6-type (space-group R3m) with a = 5.7195Å, c = 27.8655(4) Å and therefore belongs to the family of hexagonal elpasolites being the first example for an Al-elpasolite with three different alkali metals. Further insights regarding structural details could be gained using 87Rb MAS NMR spectroscopy. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.