Structure and mineralogy of layer silicates

Abstract

Because of their many novel and advanced applications, there is increasing interest in layer silicates from the scientific and technical communities. Appropriate application of these minerals requires deep understanding of their properties and of the processes where they are involved. This chapter, by providing fundamental definitions and crystal structural and chemical data pertaining to layer silicates, aims to introduce this field to new researchers and technicians, by describing the fundamental features leading to different behaviours of layer silicates in different natural or technical processes. The subject addressed is vast and so the reader is referred in some cases to work already published. The focus here is on layer silicates for which detailed crystal structures are given in the literature and which are likely to be used in an applied way in the future. Layer-silicate minerals fulfilling these requirements are: (1) kaolin-serpentine group(e.g. kaolinite, dickite, nacrite, halloysite, hisingerite, odinite, lizardite, berthierine, amesite, cronstedtite, nepouite, kellyite, fraipontite, brindleyite, guidottiite, bementite, greenalite, caryopilite; minerals of the pyrosmalite series); (2) talc and pyrophyllite groups (e.g. pyrophyllite, ferripyrophyllite, willemseite); (3) mica group (i.e. some recent advances in crystal chemistry and structure of dioctahedral and trioctahedral micas); (4) smectite group (e.g. montmorillonite, saponite, hectorite, sauconite, stevensite, swinefordite); (5) vermiculite group; (6) chlorite group (e.g. trioctahedral chlorite such as clinochlore, di,trioctahedral and dioctahedral chlorites such as cookeite and sudoite); (7) some 2:1 layer silicates involving a discontinuous octahedral sheet and a modulated tetrahedral sheet such as kalifersite, palygorskite and sepiolite; and (8) imogolite and allophane.

Surface Crystal Chemistry of Phyllosilicates Using X-Ray Photoelectron Spectroscopy: A Review

“…In addition, XPS data were compared to results obtained using other surface-sensitive techniques, such as low-energy electron diffraction (LEED), atomic force microscopy (AFM), secondary ion mass spectrometry (SIMS), Auger electron spectrometry (AES), and X-ray photoelectron diffraction (XPD). Starting from the layer silicate bulk structure, where the three-dimensional structure is well established (for a review, see Brigatti and Guggenheim, 2002;Brigatti et al, 2011;Guggenheim, 2011), the present paper considers compositional and structural aspects of freshly cleaved phyllosilicate surfaces. Phyllosilicate XPS binding energies are described here to obtain oxidation state, layer charge, and chemical bonding information from the chemical shifts of different peaks.…”

Ceramic / inorganic-organic nano-hybrid composites for thermally stable insulation of electrical wires. Part I: Composition and synthetic parameters

“…To fully exploit benefits from ceramic component, layered silicate particles becomes the choice, because they are softer than silica or alumina. This type of materials comprises numerous tetrahedral and octahedral atomic sheets stacking together with an interlayer space, where the interlayer space can be empty, occupied by cations or even inserted with foreign molecules [24]. The expandable interlayer means the layers are movable relatively to one another, implying these plate particles are bendable in some way similar to a book, so that may lessen the hardening effect of inorganic phase on the mechanical flexibility of resultant composite coatings.…”

Interlayer water molecules in organocation-exchanged vermiculite and montmorillonite: A case study of tetramethylammonium

“…The swelling clay minerals, smectite, and vermiculite, are deficient in positive layer charge because of cation substitutions either in the octahedral sheet (e.g., Mg 2+ for Al 3+ ), tetrahedral sheet (e.g., Al 3+ for Si 4+ ) or both sheets (e.g., Brigatti et al 2011 for a summary). To offset this charge deficiency, the common exchangeable cations in nature (e.g., K, Na, Mg, Fe) may enter the interlayer along with H 2 O molecules (Bailey 1980).…”