A complete crystal-chemical characterization of erionite-K from Rome, Oregon, was obtained by combining field emission scanning electron microscopy, laboratory parallel-beam transmission powder diffraction, and 57Fe Mössbauer spectroscopy. Rietveld refinement results evidenced that the most striking difference in comparison with the structure of erionite-Ca is significant K at a K2 site (1/2, 0, 0), which is empty in erionite-Ca. In addition, site Ca1 shows low occupancy and Ca3 is vacant. The oxidation and coordination state of Fe, whose occurrence was revealed by chemical analysis, have been clarified by exploiting room- and low-temperature 57Fe Mössbauer spectroscopy. The majority of Fe (95%) was attributed to Fe 3+-bearing, superparamagnetic, oxide-like nanoparticles with dimensions between 1 and 9 nm, and the remaining 5% was attributed to hematite particles with size >10 nm, both located on the crystal surface.
Crystal structure and iron topochemistry of erionite-K from Rome, Oregon, U.S.A / Ballirano, Paolo; Andreozzi, Giovanni Battista; M., Dogan; A. U., Dogan. - In: AMERICAN MINERALOGIST. - ISSN 0003-004X. - STAMPA. - 94:8-9(2009), pp. 1262-1270. [10.2138/am.2009.3163]
Crystal structure and iron topochemistry of erionite-K from Rome, Oregon, U.S.A.
BALLIRANO, Paolo;ANDREOZZI, Giovanni Battista;
2009
Abstract
A complete crystal-chemical characterization of erionite-K from Rome, Oregon, was obtained by combining field emission scanning electron microscopy, laboratory parallel-beam transmission powder diffraction, and 57Fe Mössbauer spectroscopy. Rietveld refinement results evidenced that the most striking difference in comparison with the structure of erionite-Ca is significant K at a K2 site (1/2, 0, 0), which is empty in erionite-Ca. In addition, site Ca1 shows low occupancy and Ca3 is vacant. The oxidation and coordination state of Fe, whose occurrence was revealed by chemical analysis, have been clarified by exploiting room- and low-temperature 57Fe Mössbauer spectroscopy. The majority of Fe (95%) was attributed to Fe 3+-bearing, superparamagnetic, oxide-like nanoparticles with dimensions between 1 and 9 nm, and the remaining 5% was attributed to hematite particles with size >10 nm, both located on the crystal surface.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
