EPR Study of Copper(II) Ion Pairs in Y-Type Zeolites

Abstract

The structures of identical and nonlinear Cu2+ pairs in Y-type zeolites have been studied by EPR spectroscopy. The identical pairs are formed by exchange-coupled Cu2+ ions which have the same symmetry axis and magnetic parameters. They are formed by coexchanging Cu2+ with Mg2+, Ca2+, or La3+ ions into a NaY zeolite. The spectrum is characterized by a zero field splitting of D=0.0476 cm−1. The nonlinear pairs which are formed upon more extensive Cu2+ exchange have symmetry axes that form an angle of 110° with respect to each other. These models compare favorably with the available x-ray diffraction data on CuY zeolites.