1. Departamento de Química, Laboratório de Materiais Inorgânicos, Universidade Federal de Santa Maria, 97105‐900 Santa Maria, RS, Brazil
2. Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195 Berlin, Germany, http://www.bcp.fu‐berlin.de/chemie/chemie/forschung/ InorgChem/agabram/index.html
3. Bergische Universität Wuppertal, Department of Inorganic Chemistry, Gaußstr. 20, 42119 Wuppertal, Germany