1. Crystallography & Geomaterials Research, Faculty of Geosciences, and Bremen Center for Computational Materials Science, and MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstraße 1, D-28359 Bremen, Germany
2. Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via Campi 103, I-41125 Modena, Italy
3. Department of Chemistry and NIS Centre, University of Torino, Via Giuria 7, I-10125 Torino, Italy