M?ssbauer study of the effect of rare earth substitution into montmorillonite

摘要

Novel montmorillonites were prepared by the exchange of the interlayer cations with a series of rare earth cations (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, and Er) and characterized by XRD, XRF, SEM, chemical analysis and ~(57)Fe M?ssbauer spectroscopy. An unexpected magnetically split component, assigned to iron being in the interlayer space, was observed in the M?ssbauer spectra at 78K in some rare earth cation exchanged montmorillonite. This paper is the initial report about this observation. The transition of iron from the octahedral site to the interlayer and possible incorporation of rare earths in sites different from those which are in the interlayer space was concluded.