Vibrational spectra of completely siliceous zeolite A

Zeolite A was the first commercial zeolite, and remains in use as a sorbent, molecular sieve and ion exchanger. Because of its unique structure, there has been increasing effort to understand the framework vibrations of zeolite A on a theoretical basis. Although the vibrational spectra of zeolite A have been calculated by many workers, most of the calculations include a pure silica framework to avoid the complications presented by charge-compensating cations. However, these calculations cannot be verified directly because no experimental spectra of completely siliceous zeolite A have been reported due to the fact that it is very difficult to produce. In this paper, we report, for the first time the IR and Raman spectra of completely siliceous zeolite A.