1. Contribution from the Department of Materials Science, Moscow State University, Vorob'evy Gory, Moscow 119899, Russia, Inorganic Chemistry, Royal Institute of Technology, Stockholm S 100 44, Sweden, Department of Chemistry, Moscow State University, Vorob'evy Gory, Moscow 119899, Russia, and Inorganic Chemistry Institute, Siberian Branch of RAS, Novosibirsk, Russia