1. Department of Inorganic Chemistry, National Taras Shevchenko University, Volodimirska st. 64, Kyiv 01033, Ukraine, Fax: (internat.) + 380‐44/296‐2467
2. Department of Chemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
3. Scientific Research Department of Alkali Halide Crystals, STC “Institute for Single Crystals”, National Academy of Sciences of Ukraine, Lenina Ave 60, Khar’kov 61001, Ukraine