Electron spin–echo study of the cupric ion location in hydrated A-type zeolites

Abstract

An electron spin–echo modulation study of partially cupric ion exchanged A-type zeolites in the hydrated state shows that the cupric ions are preferentially adsorbed in site S2 where they are solvated by two water molecules with a Cu—O distance of 0.20 nm. S2 is a hexagonal interior face between the α- and β-cages. One solvating water is in the β-cage and one is in the α-cage. ²⁷Al modulation in the spin–echo envelope was also detected but the modulation pattern could only be qualitatively interpreted due to a large quadrupole interaction.