(Sub)Micron CaF₂ Cubes and Hollow Rods From Ionic Liquid Emulsions

Andreas Taubert
Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
Fax: +41 61 267 3855; Tel: +41 61 267 3832; E-mail: andreas.taubert@unibas.ch

Abstract
Uniform CaF₂ cubes and rods with a well-defined crystal habit have been grown from emulsions of an ionic liquid (IL) in aqueous CaCl₂ solutions via the hydrolysis of the PF₆^– counterion of the IL. Intriguingly, at high IL contents, hollow CaF₂ rods form, which has not been observed before. The rods can reach lengths up to over ten micrometers and widths of up to ca. 2.5 mm. Furthermore, the surface of the IL droplet has a strong influence on the nucleation efficiency of the precipitating mineral.

Key words: ionic liquids, emulsions, calcium fluoride, hollow rods