Abstract
X-ray diffraction (XRD) characterization of natural and intercalated smectites is usually limited to the apparent d-value estimated from the peak maxima in the raw data. This can lead to the misinterpretation of the measured data. In the case of XRD, the interference function is modulated by instrumental factors (Lorentz-polarization factor, diffraction geometry) and physical factors (structure factor, surface roughness effect). These effects lead to diffraction profile distortions, depending on the diffraction angle and peak full width at half maximum (FWHM). As a result, the diffraction profiles for structures with large line broadening (FWHM > 1°) exhibit a significant peak shift (Δd ∼ 1.5 Å), especially at low angles (2θ ≤ 10°). The present work deals with the detailed analysis of all these effects, their corrections and their consequences for the interpretation of diffraction patterns (including possible errors in determining lattice parameters or the structure model). The investigated materials were montmorillonites (MMT) intercalated with hydroxy-Al polymers. Diffraction profile analysis revealed the corrected d-values and showed that the intercalated sample is not a mixed-layered structure. As a result a structural model of the interlayer is presented.
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Čapková P, Driessen RAJ, Numan M, Schenk H, Weiss Z, Klika Z. 1998. Molecular simulations of the montmorillo-nite intercalated with aluminium complex cations. Parts I and II. Clays Clay Miner: in press.
Figueras F, Klapyta Z, Massiani P, Mountassir Z, Tichit D, Fajula F, Gueguen C, Bousquet J, Auroux A. 1990. Use of competetive ion exchange for intercalation of montmoril-lonite with hydroxy-aluminium species. Clays Clay Miner 38:257–264.
Hsu PH. 1992. Reaction of OH-A1 polymers with smectites and vermiculites. Clays Clay Miner 40:300–305.
Ibers JA, Hamilton WC. 1974. International tables for X-ray crystallography, Vol. IV—Revised and supplementary tables. Birmingham: Kynoch Pr. 366 p.
Johansson G. 1962. The crystal structures of [Al2(OH)2(H2O)8] (SO4)2· 2H2O and [Al2(OH)2(H2O)8](SeO4)2·2H2O. Acta Chem Scand 16:403–420.
Klug HP, Alexander LE. 1974. X-ray diffraction procedures for polycrystalline and amorphous materials. New York: Wiley Intersci Publ. 966 p.
Kužzel R. 1990. Difpatan [computer program], Faculty of Math and Physics, Charles Univ, Prague, Czech Republic; available from kuzel@karlov.mff.cuni.cz.
Mitchell WI. 1990. Pillared layered structures. London: Elsevier. 252 p.
Rafaja D. 1988. Simul [computer program], Faculty of Math and Physics, Charles Univ, Prague, Czech Republic; available from rafaja@karlov.mff.cuni.cz.
Reynolds RC. 1980: Interstratified clay minerals. In: Brindley GW, Brown G, editors. Crystal structures of clay minerals and their X-ray identification. London: Mineral Soc.
Seul M, Torney DC. 1989. Statistical theory of X-ray scattering from crystals of finite size with pure displacement disorder in one dimension. Acta Crystallogr A45:381–396.
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Janeba, D., Čapková, P., Weiss, Z. et al. Characterization of Intercalated Smectites Using XRD Profile Analysis in the Low-Angle Region. Clays Clay Miner. 46, 63–68 (1998). https://doi.org/10.1346/CCMN.1998.0460107
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DOI: https://doi.org/10.1346/CCMN.1998.0460107