1. Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, 41092 Sevilla, Spain, Joint Laboratory of Solid State Chemistry of the Academy of Sciences of the Czech Republic and University of Pardubice, 530 09 Pardubice, Czech Republic, and Chemistry Laboratory, Faculty of Education, Hiroshima University, Higashi-Hiroshima 739-8524, Japan