Interstratified Clay Minerals

MacEwan, Douglas M. C.; Ruiz-Amil, A.

doi:10.1007/978-3-642-65917-1_8

Cited by 57 publications

(24 citation statements)

References 101 publications

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“…The structural character of the biotite and vermiculite is described by means of monodimensional Fourier series. The interstratified phases were studied by means of the I N T E R program (Vila & Ruiz-Amil, 1988), based on the method of MacEwan (1958) and extensions thereof (MacEwan et al, 1961, Ruiz-Amil et al, 1967. The I N T E R program permits diffraction effects from given mixtures to be calculated and compared with experimentally recorded diffraction curves.…”

Section: Methodsmentioning

confidence: 99%

Weathering of biotite to vermiculite in Quaternary lahars from Monti Ernici, Central Italy

et al. 1992

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A B S T R A C T:The weathering of biotite in Quaternary lahars from Monti Ernici (Central Italy) via interstratification stages has been studied by X-ray diffraction of both the interstratified minerals and the initial (biotite) and final (vermiculite) end-members. The structure of the biotite and vermiculite is described by means of monodimensional Fourier series. The interstratified phases have been studied using the INTER program which permits an analysis of two interstratified components by Fourier transform methods. It is shown that in the alteration range for biotite to vermiculite even small samples have different spatial concentrations of biotite, vermiculite and an intermediate biotite-vermiculite-type phase. Hydrobiotite and a rare biotite-hydrobiotite with a tendency to regularity have also been documented. Chemically, the process involves considerable oxidation of Fe 2+ and the removal of most of the elements, corresponding to a 34% loss in matter.

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Section: Methodsmentioning

confidence: 99%

Weathering of biotite to vermiculite in Quaternary lahars from Monti Ernici, Central Italy

et al. 1992

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“…The method was later extended for characterizing layercharge heterogeneities by layer-charge population histograms, using the peak-migration curve method (Lagaly and Weiss, 1975) and results from XRD experiments on randomly interstratified layers (MacEwan et al, 1961;Reynolds, 1980). This approach was used to obtain charge attributes for --200 mica-type layer silicates in an extensive study by Lagaly and Weiss (1975).…”

Section: Introductionmentioning

confidence: 99%

Application of an Internal Standard Technique by Transmission X-Ray Diffraction to Assess Layer Charge of a Montmorillonite by Using the Alkylammonium Method

Janek

Smrčok

1999

Clays and clay miner.

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Abstract--Transmission X-ray diffraction (XRD) of C6 16 alkylammonium ion-exchanged montmorillonite SAz-1 with Ag-behenate as an internal standard provided accurate estimates of d(001) values of the alkylammonium ion-exchanged montmorillonite. Inspection of d(001) values were made to assess the possible formation of gauche conformers (alternate arrangements of the molecules) in the interlayer and to determine the critical carbon chain length, n c. Using conventional constraints for nc(I' ) and nc(II) equal to 1.36 and 1.77 nm, respectively, provided ambiguous nc(I' ) and nc(II ) values. The dependence of fullwidth at half-maximum values on n c allowed better estimates of nc(I') and nc(I1) because "integral" and "non-integral" peak characteristics relating to interstratification could be included in the assessment.The effect of inaccurate estimates of nc(I') and ne(II) values on calculated interlayer cation exchange capacity (6",.) using two conventional concepts of calculation were compared. It was found that a procedure based on the summation of fractions of the layer charge gave relative errors of Ci <2%, even where the number of carbon atoms corresponding to both nc(I' ) and nc(II ) differed by -1 n c from the correct values. This method of calculation of 6,. is recommended when reliable values of C i are needed.

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“…This can be accomplished either by calculating the distribution function of the distances between first-neighbor layers (MacEwan et al 1961, MacEwan andRuiz-Amil 1975), or by comparing the experimental intensity with Copyright 9 1995, The Clay Minerals Society the theoretical intensity calculated from a structural model (Mering 1949, Kakinoki and Komura 1952, MacEwan 1956, 1958, Reynolds 1980, Plan~on 1981, Pons et al 1981, 1989, de la Calle and Suquet 1988.…”

Section: Introductionmentioning

confidence: 99%

Quantification Curves for XRD Analysis of Mixed-Layer 14Å/10Å Clay Minerals

Pons

Calle

Vidales

1995

Clays and clay miner.

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Abstract--Using theoretical profiles of diffracted X-ray intensity for interstratification between layers having d-spacings around 14.3 A and 10.1 A, a series of diagrams was derived from which the proportion of 14.3 A layers (W14) and the probability of passing from a 14.3 A layer to a 10.1 A layer (P,4/,o) can be derived. W,4 can be derived independently of P,4/~o using the angular distance between reflections situated at 18.2 ~ and 25.4 ~ 20 (CuKa). Once W~4 is determined, P,4/,o may be obtained using the angular width of the diffuse reflections between 27 ~ and 34 ~ 20. In this case, two different diagrams are proposed for Pt4/~0 determination because experimental X-ray patterns show either one or two diffuse reflections.Comparison of five experimental patterns with theoretical patterns calculated using W~4 and P,4/,0 obtained using these diagrams indicates that the method can be useful for determining W~, and P~4/~o in unknown samples. Moreover, the method described is independent of the Lorentz polarization factor and the layer type. The d-spacings associated with the two kinds of layers, however, should be similar (+ 1%) to those for which the determinative diagrams were calculated.

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Interstratified Clay Minerals

Cited by 57 publications

References 101 publications

Weathering of biotite to vermiculite in Quaternary lahars from Monti Ernici, Central Italy

Weathering of biotite to vermiculite in Quaternary lahars from Monti Ernici, Central Italy

Application of an Internal Standard Technique by Transmission X-Ray Diffraction to Assess Layer Charge of a Montmorillonite by Using the Alkylammonium Method

Quantification Curves for XRD Analysis of Mixed-Layer 14Å/10Å Clay Minerals

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