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Talc, Fe-rich
'Images of Clay'

EMU Notes in Mineralogy - volume 11

Layered mineral structures and their Application in Advanced Technologies
(M.F. Brigatti and A. Mottana, editors)

Chapter 2: An Overview of order/disorder in hydrous phyllosilicates

Stephen Guggenheim

The purpose of the chapter is to provide a condensed introduction for later chapters. Major features of atomic order and disorder in hydrous phyllosilicates are presented. Emphasis is on layer charge and the effects of cation distributions, layer stacking (polytypism), interstratified systems, modulated phyllosilicates and non-planar structures. Idealized phyllosilicate models are presented along with adjustments that structures require to compensate for lateral misfit of the semi-rigid component tetrahedral and octahedral sheets. Standard polytypes and interstratified structures are described along with the X-ray diffraction effects of both. Details of modulated systems and polysome relationships are given. In addition, the effects of the phyllosilicate interface with aqueous fluids and biomolecules are discussed.

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