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Título:
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Octahedral cation distribution in palygorskite
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Autores:
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Chryssikos, Georgios D. ;
Gionis, Vassilis ;
Kacandes, Georges H. ;
Stathopoulou, Elizabeth T. ;
Súarez Barrios, Mercedes ;
García Romero, Emilia ;
Sánchez del Río, Manuel
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Tipo de documento:
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texto impreso
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Editorial:
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Mineralogical Society of America, 2009
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Dimensiones:
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application/pdf
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Nota general:
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info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Geología: Mineralogía
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Tipo = Artículo
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Resumen:
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The OH speciation of 18 palygorskite samples from various localities were evaluated by near infrared spectroscopy (NIR) and compared to the corresponding octahedral composition derived from independent, single-particle analytical electron microscopy (AEM). NIR gives evidence for dioctahedral-like (AlAlOH, AlFe3+OH, Fe3+Fe3+OH) and trioctahedral-like (Mg3OH) species. Therefore, palygorskite can be approximated by the formula yMg5 Si8O20(OH)2·(1 – y)[xMg2Fe2·(1 – x)Mg2Al2]Si8O20(OH)2, where x is the Fe content of the dioctahedral component, and y is the trioctahedral fraction. The values of x estimated from the NIR data are in excellent agreement with the Fe/(VIAl + Fe) ratio from AEM (R2 = 0.98, ? = 0.03), thus suggesting that all octahedral Al and Fe in palygorskite participate in M2M2OH (dioctahedral-like) arrangements. Furthermore, y values from AEM can be compared to NIR (R2 = 0.90 and ? = 0.05) after calibrating the relative intensity of the Mg3OH vs. (Al,Fe)2OH overtone bands using AEM data. The agreement between the spectroscopic and analytical data are excellent. The data show that Fe3+ for Al substitution varies continuously in the analyzed samples over a broad range (0
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En línea:
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https://eprints.ucm.es/id/eprint/21635/1/2009_AmMin_Chryssikos_p200-203.pdf
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