Hostname: page-component-745bb68f8f-hvd4g Total loading time: 0 Render date: 2025-02-04T21:49:28.407Z Has data issue: false hasContentIssue false
  • English
  • Français

Rietveld Refinement of Disordered Illite-Smectite Mixed-Layer Structures by a Recursive Algorithm. II: Powder-Pattern Refinement and Quantitative Phase Analysis

Published online by Cambridge University Press:  01 January 2024

Kristian Ufer ,
Reinhard Kleeberg ,
Jörg Bergmann  and
Reiner Dohrmann
Kristian Ufer*
Affiliation:
Institute of Mineralogy, TU Bergakademie Freiberg, Brennhausgasse 14, 09596 Freiberg, Germany BGR/LBEG, Stilleweg 2, 30655 Hannover, Germany
Reinhard Kleeberg
Affiliation:
Institute of Mineralogy, TU Bergakademie Freiberg, Brennhausgasse 14, 09596 Freiberg, Germany
Jörg Bergmann
Affiliation:
Ludwig-Renn-Allee 14, 01217 Dresden, Germany
Reiner Dohrmann
Affiliation:
BGR/LBEG, Stilleweg 2, 30655 Hannover, Germany
*
*E-mail address of corresponding author: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

X-ray diffraction (XRD) of powdered materials is one of the most common methods used for structural characterization as well as for the quantification of mineral contents in mixtures. The application of the Rietveld method for that purpose requires structure models for each phase. The recursive calculation of structure factors was applied here to the Rietveld refinement of XRD powder patterns of illite-smectite (I-S) minerals. This approach allowed implementation of stacking disorder in structural models. Models for disordered stacking of cis-vacant and trans-vacant dioctahedral 2:1 layers as well as rotational disorder were combined with models for mixed layering of illitic and smectitic layers.

The DIFFaX code was used to simulate non-basal (hk) reflections of illites with different degrees of disorder. Rietveld refinements of these simulated patterns were used to evaluate the application of this new approach. A model describing rotational disorder (n·120° and n·60° rotations) and mixed layering of cis-vacant and trans-vacant dioctahedral layers was tested. Different starting parameters led to identical results within the ranges of standard deviations and confirmed the stability of the automatic refinement procedure. The influence on the refinement result of an incorrect choice of fixed parameters was demonstrated.

The hk model was combined with models describing the basal reflections of disordered I-S and tested on measured data. A glauconitic mineral (Urkut, Hungary), an ordered I-S (ISCz-1, a special clay in the Source Clays Repository of The Clay Minerals Society), and a dioctahedral I-S (F4, Füzérradvány, Hungary) were used as test substances. Parameters describing the mixed layering of illitic and smectitic layers were compared with the results from refinements of oriented mounts and showed good agreement. A pattern of a physical mixture of an I-S mineral and a turbostratically disordered smectite was analyzed in order to test the new approach for application in quantitative phase analysis. The quantitative Rietveld phase analysis results were found to be satisfactory.

Keywords

BGMNDIFFaXIllite-smectiteQuantitative Phase AnalysisRietveld RefinementStacking Faults
Type
Article
Information
Clays and Clay Minerals , Volume 60 , Issue 5 , October 2012 , pp. 535 - 552
Copyright
Copyright © Clay Minerals Society 2012

Footnotes

†

Deceased

References

Altaner, S.P. and Ylagan, R.F., 1997 Comparison of structural models of mixed-layer illite/smectite and reaction mechanisms of smectite illitization Clays and Clay Minerals 45 517–533.CrossRefGoogle Scholar
Bergmann, J. Friedel, P. and Kleeberg, R., 1998 BGMN — a new fundamental parameter based Rietveld program for laboratory X-ray sources, its use in quantitative analysis and structure investigations CPD Newsletter, Commission of Powder Diffraction, International Union of Crystallography 20 5–8.Google Scholar
Cheary, R.W. and Coelho, A., 1992 Fundamental parameters approach to x-ray line-profile fitting Journal of Applied Crystallography 25 109–121.CrossRefGoogle Scholar
Drits, V.A. and Sakharov, B.A., 1976 X-ray Analysis of Mixed-layer Clay Minerals Moscow Nauka 256 pp..Google Scholar
Drits, V.A. and Tchoubar, C., 1990 X-ray Diffraction by Disordered Lamellar Structures Berlin, Heidelberg Springer-Verlag.CrossRefGoogle Scholar
Drits, V.A. McCarty, D.K. and Zviagina, B.B., 2006 Crystal-chemical factors responsible for the distribution of octahedral cations over trans- and cis-sites in dioctahedral 2:1 layer silicates Clays and Clay Minerals 54 131–152.CrossRefGoogle Scholar
Howard, S.A. and Preston, K.D., 1989 Profile fitting of powder diffraction patterns Modern Powder Diffraction 20 217–275.CrossRefGoogle Scholar
MacEwan, D.M.C., 1956 Fourier transform methods for studying scattering from lamellar systems. I. A direct met hod for analyzing interstratified mixtures Kolloidzeitschrift 149 96–108.Google Scholar
Méring, J., 1949 L’interférence des rayons X dans les systèmes à stratification désordonnée Acta Crystallographica 2 371–377.CrossRefGoogle Scholar
Nadeau, P.H. Wilson, M.J. McHardy, W.J. and Tait, J.M., 1984 Interstratified clays as fundamental particles Science 225 923–925.CrossRefGoogle ScholarPubMed
Reynolds, R.C., 1992 X-ray diffraction studies of illite/smectite from rocks, <1 mm randomly oriented powders, and <1 mm oriented powder aggregates: The absence of laboratory-induced artifacts Clays and Clay Minerals 40 387–396.CrossRefGoogle Scholar
Sakharov, B.A. Besson, G. Drits, V.A. Kameneva, M.Y. Salyn, A.L. and Smoliar, B.B., 1990 X-ray study of the nature of stacking faults in the structure of glauconites Clay Minerals 25 419–435.CrossRefGoogle Scholar
Scarlett, N.V. and Madsen, I.C., 2006 Quantification of phases with partial or no known crystal structures Powder Diffraction 21 278–284.CrossRefGoogle Scholar
Taylor, J.C. and Matulis, C.E., 1994 A new method for Rietveld clay analysis: Part 1. Use of a universally measured standard profile for Rietveld quantification of montmorillonites Powder Diffraction 9 119–123.CrossRefGoogle Scholar
Treacy, M.M. Newsam, J.M. and Deem, M.W., 1991 A general recursion method for calculating diffracted intensities from crystals containing planar faults Proceedings of the Royal Society of London A433 499–520.Google Scholar
Tsipursky, S.I. and Drits, V.A., 1984 The distribution of octahedral cations in the 2:1 layers of dioctahedral smectites studied by oblique-texture electron diffraction Clay Minerals 19 177–193.CrossRefGoogle Scholar
Ufer, K. Kleeberg, R. Bergmann, J. Curtius, H. and Dohrmann, R., 2008 Refining real structure parameters of disordered layer structures within the Rietveld method Zeitschrift für Kristallographie Supplements 27 151–158.CrossRefGoogle Scholar
Ufer, K. Stanjek, H. Roth, G. Dohrmann, R. and Kaufhold, S., 2008 Quantitative phase analysis of bentonites by the Rietveld method Clays and Clay Minerals 56 272–282.CrossRefGoogle Scholar
Ufer, K. Kleeberg, R. Bergmann, J. and Dohrmann, R., 2012 Rietveld refinement of disordered illite-smectite mixed layer structures by a recursive algorithm. I: One-dimensional patterns Clays and Clay Minerals 60 508–535.Google Scholar
Warren, B.E., 1941 X-ray diffraction in random layer lattices Physical Review 59 693–698.CrossRefGoogle Scholar