1. Tomsk Polytechnic University, Institute of Physics and Technology, Applied Chemistry of Rare Elements Department 30 Lenina Avenue, Tomsk 634050, Russia
2. AG Fluorchemie, Department Chemie, Technische Universität München Lichtenbergstraße 4, 85747 Garching, Germany, http://www.ch.tum.de/fkraus/kraus.html