1. Department of Inorganic Chemistry , Ivan Franko National University of Lviv , Kyryla i Mefodiya St. 6, 79005 L’viv , Ukraine
2. Kruty Heroes Lviv Lyceum with Intensive Military and Physical Training , Pasichna Str. 68, 79038 L’viv , Ukraine
3. Institute of Low Temperature and Structure Research, Polish Academy of Sciences , ul. Okólna 2, 50-422 Wroclaw , Poland