Ab Initio Determination of Edge Surface Structures for Dioctahedral 2:1 Phyllosilicates: Implications for Acid-Base Reactivity

  title={Ab Initio Determination of Edge Surface Structures for Dioctahedral 2:1 Phyllosilicates: Implications for Acid-Base Reactivity},
  author={Barry R. Bickmore and Kevin M. Rosso and Kathryn L. Nagy and Randall T. Cygan and Christopher J. Tadanier},
  journal={Clays and Clay Minerals},
The atomic structure of dioctahedral 2:1 phyllosilicate edge surfaces was calculated using pseudopotential planewave density functional theory. Bulk structures of pyrophyllite and ferripyrophyllite were optimized using periodic boundary conditions, after which crystal chemical methods were used to obtain initial terminations for ideal (110)- and (010)-type edge surfaces. The edge surfaces were protonated using various schemes to neutralize the surface charge, and total minimized energies were… 

Figures and Tables from this paper

A Study on Edge Surface Structures and Reactivity for Clay Minerals by Molecular Orbital Method
To clarify the dissolution mechanism of clay minerals, the basal and edge surface structures of dioctahedral 2:1 phyllosilicate were optimized using the semiempirical molecular orbital method. The
Uranyl adsorption on solvated edge surfaces of pyrophyllite: a DFT model study.
According to the results, several adsorption species, with different coordination numbers on different edge faces, may coexist on clay minerals and this computational finding rationalizes why earlier spectroscopic studies indicated the existence of more than one adsorptive species.
Stability of dioctahedral 2:1 phyllosilicate edge structures based on pyrophyllite models
Phyllosilicates and related clay minerals are of interest due to a variety of technological applications and impact on natural soils. The important properties of these layered minerals arise from
Na-Montmorillonite Edge Structure and Surface Complexes: An Atomistic Perspective
The edges of montmorillonite (MMT) react strongly with metals and organic matter, but the atomic structure of the edge and its surface complexes are not unambiguous since the experimental isolation
Origin of 6-fold coordinated aluminum at (010)-type pyrophyllite edges
To better understand the aqueous chemical reactivity of clay mineral edges we explored the relationships between hydration and the structure of (010)-type edges of pyrophyllite. In particular, we
Edge Structure of Montmorillonite from Atomistic Simulations
Classical molecular dynamics (MD) simulations have been performed to investigate the effects of substitutions in the octahedral sheet (Mg for Al) and layer charge on an atomistic model of the


A Novel Method to Correlate Layer Charge and the Catalytic Activity of 2:1 Dioctahedral Smectite Clays in Terms of Binding the Interlayer Cation Surrounded by Monohydrate
Ab initio total energy pseudopotential calculations were performed on 2:1 dioctahedral smectite to rationalize an understanding of the structure and energetics for the same and to correlate catalytic
Analysis and Implications of the Edge Structure of Dioctahedral Phyllosilicates
Crystal growth theory was applied to describe edge sites of phyllosilicates. Three face configurations were found to exist. One face has one tetrahedral site per tetrahedral sheet and two octahedral
In situ atomic force microscopy study of hectorite and nontronite dissolution: Implications for phyllosilicate edge surface structures and dissolution mechanisms
Abstract The dissolution behavior of two smectite minerals, hectorite (trioctahedral) and nontronite (dioctahedral), was observed in situ, in acid solutions, using atomic force microscopy. As
Ab-initio total energy study of uncharged 2:1 clays and their interaction with water
Ab-initio total energy pseudopotential calculations were performed on talc and pyrophyllite to assess the success of the method in determining the structure of layered silicates. The calculated
The Surface Coulomb Energy And Proton Coulomb Potentials Of Pyrophyllite {010}, {110}, {100}, and {130} EDGES
This paper describes structural models of four pyrophyllite edge faces: {010}, {110}, {100}, and {130}. Water molecules chemisorbed to Lewis acid sites stabilize edge faces both crystallochemically
Molecular Controls on Kaolinite Surface Charge
No basal plane participation is required to explain the site densities determined from proton adsorption isotherms, and independent evidence from scanning force microscopy points to a higher percentage of edge surface area due to thicker particles and basal surface steps than previously assumed.
Is silica really an anomalous oxide? Surface acidity and aqueous hydrolysis revisited.
  • Nita Sahai
  • Chemistry
    Environmental science & technology
  • 2002
The single-site Solvation, Bond Strength, and Electrostatic (SBE) model accounts for the anomalous position of silica onthe surface acidity versus aqueous acidity correlation developed for metal
Acid Hydrolysis of Octahedral Mg2+ Sites in 2:1 Layered Silicates: An Assessment of Edge Attack and Gallery Access Mechanisms
The acid hydrolysis products of trioctahedral fiuorohectorite and phlogopite have been investigated by XRD, MAS NMR spectroscopy and nitrogen BET surface area analysis in an effort to assess the