Person: García Rivas, Javier
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First Name
Javier
Last Name
García Rivas
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Cristalografía y Mineralogía
Identifiers
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Item An insight in the structure of a palygorskite from Palygorskaja: Some questions on the standard model(Applied clay science, 2017) García Rivas, Javier; Sánchez del Río, Manuel; García Romero, Emilia; Suárez, MercedesIn this study we analyze in detail a palygorskite from Palygorskaja. This palygorskite is situated in the context of the existing studies using X-ray powder diffraction analysis. Moreover, a novel microdiffraction study on a small bunch of fibers shows highly structured 2D diffraction patterns that allow to decipher some information on the microstructure, thus overcoming the uncertainty usually originated by large samples containing mixtures and impurities. Structural data provided by Chisholm (1992) are used to simulate 1D and 2D powder and fiber diffraction patterns for palygorskite, which are compared with the experimental results. We performed simulations for powder and fiber diffraction and we centered our attention in the region of interest with d-spacings between 4.0 and 4.5 Å. This palygorskite is consistent with a purely orthorhombic palygorskite, based on good agreement of data with simulations. The experimental results present some reflections not found in the simulations. These reflections are interpreted as corresponding to other hk1 planes of palygorskite. They do not match any reflection from the monoclinic structural model nor from probable impurities, reinforcing the interpretation of them being intrinsic to the structure of the mineral. Our findings suggest a revisal of the commonly accepted structure of palygorskite. They correspond to hk1 planes of palygorskite, and they do not match any reflection neither from the monoclinic structural model nor from possible impurities, and thus reinforcing the idea of them being intrinsic to the structure of the mineral, suggesting the necessity of a revisal of the commonly accepted structure of palygorskite.