Mössbauer spectroscopic study of ferrisilicate analog of zeolite BETA

Mössbauer spectroscopic studies on an as-synthesized sample of ferrisilicate analog of zeolite BETA, which was substantially free from Al (SiO₂/Al₂O₃ > 2000) have been carried out at rt, 4.2 K, and in the presence of an externally applied field (4.13 T) at 4.2 K. The broadness of the sole peak in the spectra recorded at rt. and at 4.2 K, isomer shift (IS) of 0.22 mm/s at rt. and 0.32 mm/s at 4.2 K, and the quite narrow and sharp hyperfine sextet in the spectrum of 4.2 K with externally applied field (4.13 T), clearly demonstrate that most of the Fe³⁺ ions, if not all, are well dispersed and present in the tetrahedral framework of zeolite BETA.