Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-29T07:07:22.218Z Has data issue: false hasContentIssue false
  • English
  • Français

Angle-Resolved X-Ray Photoelectron Studies of Cleavage in Chlorites

Published online by Cambridge University Press:  28 February 2024

Stephen Evans  and
Anthony G. Hiorns
Stephen Evans
Affiliation:
Electron Spectroscopy Laboratory, Institute of Earth Studies, University of Wales Aberystwyth, Dyfed, SY23 3DB, U.K.
Anthony G. Hiorns*
Affiliation:
Electron Spectroscopy Laboratory, Institute of Earth Studies, University of Wales Aberystwyth, Dyfed, SY23 3DB, U.K.
*
†Present address: English China Clays International, John Keay House, St. Austell, Cornwall.
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.

The cleavage of two single-crystal chlorites (a clinochlore and a penninite) has been studied using angle-resolved X-ray photoelectron spectroscopy (XPS). Both minerals cleaved in regions not typical of the bulk; the composition of the clinochlore was found to be especially non-uniform. The brucitic interlayer divided evenly between the pair of new surfaces exposed for two cleaves in the clinochlore, but was partitioned unequally in two cleaves in the penninite. The differences in apparent composition between the complementary pairs of surfaces are interpreted to show a marked preference of octahedral Al for the brucitic layer, in agreement with X-ray bulk structure refinements. For both chlorites, the layer charge was reduced in regions of easy cleavage, which also had a higher proportion of Si and less tetrahedral Al than the bulk chlorite. The percentages of tetrahedral aluminium deduced from the XPS surface analyses agreed satisfactorily with the percentages independently determined by consideration of the magnitude of anisotropy in the X-ray photoelectron diffraction (XPD) patterns. The XPD patterns from the clinochlore for rotation about axes parallel and antiparallel to the crystallographic a-axis were identical, showing that tetrahedral ordering was absent.

Keywords

ChloriteCleavageESCAPhotoelectronStructureXPS
Type
Research Article
Information
Clays and Clay Minerals , Volume 44 , Issue 3 , June 1996 , pp. 398 - 407
Copyright
Copyright © 1996, The Clay Minerals Society

References

Adams, J.M., Evans, S. and Thomas, J.M.. 1978. X-ray photoelectron diffraction: A new technique for structural studies of complex solids. J Am Chem Soc 100: 3260–3262.CrossRefGoogle Scholar
Ash, L.A. and Evans, S.. 1993. X-ray photoelectron diffraction studies of the surface chemistry of non-stoichiometric synthetic spinel. Surf Interface Anal 20: 1075–1080.CrossRefGoogle Scholar
Ash, L.A., Evans, S. and Hiorns, A.G.. 1987. Cation ordering in lepidolite and biotite studied by X-ray photoelectron diffraction. Clay Miner 22: 375–386.CrossRefGoogle Scholar
Ash, L.A., Clark, S.L., Evans, S. and Hiorns, A.G.. 1988. X-ray photoelectron diffraction studies of the micas lepidolite and biotite. J Chem Soc, Dalton Trans 859–879.Google Scholar
Bailey, S.W.. 1988. Chlorites: Structures and crystal chemistry. In: Mineralogical Society of America reviews in mineralogy 19: 347–403.Google Scholar
Bailey, S.W. and Brown, B.E.. 1962. Chlorite polytypism: I Regular and semi-random one-layer structures. Am Mineral 47: 819–850.Google Scholar
Bennett, H. and Reed, R.A.. 1971. Chemical methods of silicate analysis. London: Academic Press. p 73–79.Google Scholar
Deer, W.A., Howie, R.A. and Zussman, J.. 1962. Rock forming minerals, Vol. 3, Sheet silicates. London: Longman. p 131–136.Google Scholar
Egelhoff, W.F.. 1984. X-ray photoelectron and Auger-electron forward scattering—a new tool for studying epitaxial growth and core-level binding energy shifts. Phys Rev B 30: 1052–1055.CrossRefGoogle Scholar
Evans, S.. 1992. Estimation of the uncertainties associated with XPS peak intensity determination. Surf Interface Anal 18: 323–332.CrossRefGoogle Scholar
Evans, S., Adams, J.M. and Thomas, J.M.. 1979a. The surface structure and composition of layered silicate minerals: Novel insights from X-ray photoelectron diffraction, K-emission spectroscopy and cognate techniques. Phil Trans R Soc Lond A 292: 563–591.Google Scholar
Evans, S. and Elliott, D.A.. 1982. Interfacing AEI/Kratos electron spectrometers to a microcomputer for data acquisition and processing. Surf Interface Anal 4: 267–270.CrossRefGoogle Scholar
Evans, S. and Hiorns, A.G.. 1986. Convolutional smoothing algorithms in electron spectroscopy. Surf Interface Anal 8: 71–73.CrossRefGoogle Scholar
Evans, S., Pritchard, R.G. and Thomas, J.M.. 1978. Relative differential subshell photoionisation cross-sections (Mg Kα) from lithium to uranium. J Electron Spectrosc Rel Phen 14: 341–358.CrossRefGoogle Scholar
Evans, S. and Raftery, E.. 1982. X-ray photoelectron diffraction studies of lepidolite. Clay Miner 17: 443–452.CrossRefGoogle Scholar
Evans, S., Raftery, E. and Thomas, J.M.. 1979b. Angular variations in core-level XPS peak intensity ratios from single-crystal solids. Surf Sci 89: 64–75.CrossRefGoogle Scholar
Foster, M.D.. 1962. Interpretation of the composition and a classification of the chlorites. U.S. Geol Surv Prof Paper 414-A: 1–33.CrossRefGoogle Scholar
Henderson, G.S., Vrdoljak, G.A., Eby, R.K., Wicks, F.J. and Rachlin, A.L.. 1994. Atomic-force microscopy studies of layer silicate minerals. Coll Surf A—Physicochem Engineer Aspects 87: 197–212.CrossRefGoogle Scholar
Hiorns, A.G.. 1991. Applications of electron spectroscopy in inorganic chemistry. [Ph.D. Thesis]. Aberystwyth: University of Wales. p 96–114.Google Scholar
Seah, M.P. and Dench, W.A.. 1979. Quantitative electron spectroscopy of surfaces: A standard data base for electron inelastic mean free paths in solids. Surf Interface Anal 1: 2–19.CrossRefGoogle Scholar
Steinfink, H.. 1958. The crystal structure of chlorite. I. A monoclinic polymorph. Acta Crystallog 11: 191–195.CrossRefGoogle Scholar
Vrdoljak, G.A., Henderson, G.S., Fawcett, J.J. and Wicks, F.J.. 1994. Structural relaxation of the chlorite surface imaged by the atomic-force microscope. Am Mineral 79: 107–112.Google Scholar