title: Optical anomaly in artificial cubic hieratite, K2[SiF6].
abstract: Crystals of K2[SiF6] were grown in agar gel, silica gel and jelly. Crystals grown in agar gel or jelly exhibit birefringence and consist of six double refracting growth sectors, each having the shape of a tetragonal pyramid. Nevertheless, the structure of the crystals from agar gel could be refined as cubic (space group Fm3m) with a weighted R factor of 0.043. The amount of birefringence was estimated by the Senarmont compensation method and the rotating polarizer method.
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
authors.forename: Ole F
authors.initials: OF
authors.lastname: Göbel
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
authors.forename: Johan E
authors.initials: JE
authors.lastname: ten Elshof
authors.affiliation: Department of Chemistry, University of Washington, Seattle, USA.
authors.forename: Werner
authors.initials: W
authors.lastname: Kaminsky
authors.affiliation: Bruker Nano GmbH, Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hannss
keywords: Senarmont compensation method; birefringence; optical anomaly; rotating polarizer method