Abstract: The location of cations in LaNaYzeolites with various lanthanum contents(from 1.5 to 18.7 La ions/u.c.) has been studied by ¹²⁹Xe NMR technique.It is found that all LaNaY samples pretreated at 350℃ in vacuum,even with low lanthanum content,have some lanthanum cations remaining in supercages,and the amount of cations in supercages depends on the total content of lanthanum in zeolites,When the lanthanum content exceeds 8La ions/u.c.,couples of lanthanum cations appear in sodalites(β cages),and irreversibly form bridging lanthanum oxide or oxyhydroxide species at temperature 350℃,but below this content,the reaction doesn't occur,and lanthanum cations located in different sodalites,respectively,Usually,Na¹²⁹ cations in Yzeolite as a whole are considered as being independent of the chemical shift of Xe atoms,but according to our result of ¹²⁹Xe NMR,the unlocated Na¹²⁹cations in supercage have an interaction with Xe and affect the chemical shift of xenon.

Key words: ¹²⁹Xe NMR, LaNaY Zeolite, Cation Location