FORMATION OF ALKALI-METAL PARTICLES IN ALKALI-METAL CATION EXCHANGED X-ZEOLITE EXPOSED TO ALKALI-METAL VAPOR - CONTROL OF METAL-PARTICLE IDENTITY

The series of five alkali metal (M2) vapors formed by alkali metal azide decomposition were reacted with the series of alkali metal (M1) cation exchanged X zeolites to form alkali metal particles. For Rb+ and Cs+ exchanged X zeolites, Rb(n) and Cs(n) metal particles are formed regardless of the choice of M2 vapor, so the cluster atoms must originate from the exchanged cations rather than the alkali metal vapor atom. Rb and Cs vapors exposed to any other alkali metal cation exchanged X zeolite (Li, Na, K) give Rb(n) and Cs(n) metal clusters, respectively, except for Cs/K-X. For the other M2/M1-X systems the metal particle seems to be formed from the M2 metal vapor atoms, except for Na/Li-X. These results are discussed in terms of electron-transfer energetics, electron transfer via the zeolite framework, ion and atom sizes relative to ring sizes in the zeolite framework, and ion/atom migration.