Advertisement

Clays and Clay Minerals

, Volume 41, Issue 3, pp 305–316 | Cite as

The Surface Coulomb Energy And Proton Coulomb Potentials Of Pyrophyllite {010}, {110}, {100}, and {130} EDGES

  • William F. Bleam
  • Gereon J. Welhouse
  • Mark A. Janowiak
Article

Abstract

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 and electrostatically. The detailed assignment of protons to surface oxygens and the orientation of OH bond-vectors both influence the surface Coulomb energy.

The geometry chosen for the electrostatic calculations was infinite pyrophyllite ribbon the thickness of a single phyllosilicate layer and the width of 50 to 70 unit cells. Such a phyllosilicate ribbon has only two edges, a top and bottom, which were simulated using the edge-face models mentioned above. About 94% of the surface Coulomb energy is confined to the edge-face repeat unit. The surface Coulomb energies of the four edge faces are on the order of 2–3 nJ/m, varying ± 1 nJ/m with proton assignment. The Coulomb potential, measured either within the layer or parallel to the layer, has a distinct negative trend near the edge face that can be traced to chemisorbed water molecules. Finally, the correlation between proton Coulomb potentials at the edge face and the coordination environment of the protons is poor, obscured by long-range interactions.

Key Words

Edge structure Electrostatic potential Lattice sum Pyrophyllite 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Andre, J. M., Fripiat, J. G., Demanet, C., Bredas, J. L., and Delhalle, J. (1978) Long-range Coulombic interactions in the theory of polymers: A statement of the problem and a method for calculation by the Fourier transformation method: Int. J. Quantum Chem. Quantum Chem. Symp. 12, 233–247.Google Scholar
  2. Bleam, W. F. (1990) The electrostatic potential at the basal {001} surface of talc and pyrophyllite as related to tetra-hedral-sheet distortions: Clays & Clay Minerals 38, 522–526.CrossRefGoogle Scholar
  3. Brown, I. D. and Shannon, R. D. (1973) Empirical bond-strength-bond-length curves for oxides: Acta Cryst. A 29, 266–282.CrossRefGoogle Scholar
  4. Coker, H. (1983) Elementary methods for the evaluation of electrostatic potentials in ionic crystals: J. Phys. Chem. 87, 2512–2525.CrossRefGoogle Scholar
  5. Davis, J. A. and Kent, D. B. (1990) Surface complexation modeling in aqueous geochemistry: Rev. Mineral 23, 177–260.Google Scholar
  6. Delhalle, J., Fripiat, J. G., and Piela, L. (1980) On the use of Laplace transform to evaluate one-dimensional lattice summations in quantum calculations of model polymers: Int. J. Quantum Chem. Quantum Chem. Symp. 14, 431–442.Google Scholar
  7. Eyjen, H. M. (1932) On the stability of certain heteropolar crystals: Phys. Rev. 39, 675–687.CrossRefGoogle Scholar
  8. Ewald, P. P. (1921) Die Berechnung optischer und elektrostatischer Gitterpotentiale: Ann. Phys. (Leipzig) 64, 253–287.CrossRefGoogle Scholar
  9. Ferris, A. P. and Jepson, W. B. (1975) The exchange capacities of kaolinite and the preparation of homoionic clays: J. Colloid Interface Sci. 51, 245–259.CrossRefGoogle Scholar
  10. Fripiat, J. G. and Delhalle, J. (1979) Fourier representation of the Coulombic contributions to polymer chains: J. Cornput. Phys. 33, 425–431.CrossRefGoogle Scholar
  11. Giese, R. F. (1976) Hydroxyl orientations in gibbsite and bayerite: Acta Cryst. B 32, 1719–1723.CrossRefGoogle Scholar
  12. Giese, R. F. (1979) Hydroxyl orientations in 2:1 phyllosilicates: Clay & Clay Minerals 27, 213–223.CrossRefGoogle Scholar
  13. Giese, R. F. (1984) Electrostatic energy models of micas: Rev. Mineral 13, 105–144.Google Scholar
  14. Glasser, M. L. and Zucker, I. J. (1980) Lattice sums: Theoret. Chem. Adv. Perspect. 5, 67–139.CrossRefGoogle Scholar
  15. Grim, R. E. and Guven, N. (1978) Bentonites: Geology, Mineralogy, Properties and Uses: Elsevier, Amsterdam, 256 pp.Google Scholar
  16. Harris, F.E. (1972) Fourier representation methods for electronic structures of linear polymers: J. Chem. Phys. 56, 4422–4425.CrossRefGoogle Scholar
  17. Harris, F. E. (1975) Hartree-Fock studies of electronic structures of crystalline solids: Theoret. Chem. Adv. Perspect. 1, 147–218.CrossRefGoogle Scholar
  18. Hartman, P. (1982) On the growth of dolomite and kaolinite crystals: Neu. Jahr. Mineral. Monat. 1982, 84–92.Google Scholar
  19. Hartman, P. and Perdok, W. G. (1955a) On the relations between structure and morphology of crystals. I: Acta Cryst. 8, 49–52.CrossRefGoogle Scholar
  20. Hartman, P. and Perdok, W. G. (1955b) On the relations between structure and morphology of crystals. II: Acta Cryst. 8, 521–524.CrossRefGoogle Scholar
  21. Hartman, P. and Perdok, W. G. (1955c) On the relations between structure and morphology of crystals. III: Acta Cryst. 8, 524–529.Google Scholar
  22. Hiemstra, T., van Riemsdijk, W. H., and Bolt, G. H. (1989) Multisite proton adsorption modeling at the solid/solution interface of (hydr)oxides: A new approach: J. Colloid Interface Sci. 133, 91–104.CrossRefGoogle Scholar
  23. Leadbetter, A. J., Ward, R. C., Clark, J. W., Tucker, P. A., Matsuo, T., and Suga, H. (1985) The equilibrium low-temperature structure of ice: J. Chem. Phys. 82, 424–428.CrossRefGoogle Scholar
  24. Lee, J. H. and Guggenheim, S. (1981) Single crystal x-ray refinement of pyrophyllite-1Tc: Am. Mineral. 66, 350–357.Google Scholar
  25. Muljadi, D., Posner, A. M., and Quirk, J. P. (1966) The mechanism of phosphate adsorption by kaolinite, gibbsite, and pseudoboehmite: J. Soil Sci. 17, 230–237.CrossRefGoogle Scholar
  26. O’Keeffe, M. (1989) The prediction and interpretation of bond lengths in crystals: Struct. bonding (Berlin) 71, 161–190.CrossRefGoogle Scholar
  27. O’Keeffe, M. and Stuart, J. A. (1983) Bond energies in solid oxides: Inorg. Chem. 22, 177–179.CrossRefGoogle Scholar
  28. Parks, G. A. (1990) Surface energy and adsorption at mineral-water interfaces: An introduction: Rev. Mineral 23, 133–175.Google Scholar
  29. Parry, D.E. (1975) The electrostatic potentialin the surface region of an ionic crystal: Surface Sci. 49, 433–440.CrossRefGoogle Scholar
  30. Pauling, L. (1929) The principles determining the structure of complex ionic crystals: J. Amer. Chem. Soc. 51, 1010–1026.CrossRefGoogle Scholar
  31. Press, W. H., Flannery, B. P., Teukolsky, S. A., and Vetterling, W. T. (1989) Numerical Recipes in Pascal. The Art of Scientific Computing: Cambridge, New York, 759 pp.Google Scholar
  32. Quirk, J. P. (1960) Negative and positive adsorption of chloride by kaolinite: Nature 188, 253–254.CrossRefGoogle Scholar
  33. Russell, J. D., Paterson, E., Fraser, A. R., and Farmer, V. C. (1975) Adsorption of carbon dioxide on goethite (α-FeOOH) surfaces, and its implications for anion adsorption: J. Chem. Soc., Faraday Trans. 1 71, 1623–1630.CrossRefGoogle Scholar
  34. Schindler, P. W. and Stumm, W. (1987) The surface chemistry oxides, hydroxides and oxide minerals: in Aquatic Surface Chemistry, W. Stumm, ed., Wiley, New York, 83–110.Google Scholar
  35. Schofield, R. K. and Samson, H. R. (1953) The deflocculation of kaolinite suspensions and the accompanying change-over from positive to negative chloride adsorption: Clay Mineral Bull. 2, 45–51.CrossRefGoogle Scholar
  36. Schofield, R. K. and Samson, H. R. (1954) Flocculation of kaolinite due to the attraction of oppositely charged crystal faces: Disc. Faraday Soc, 135–145.Google Scholar
  37. Secor, R. B. and Radke, C. J. (1985) Spillover of the diffuse double layer on montmorillonite particles: J. Colloid Interface Set. 103, 237–244.CrossRefGoogle Scholar
  38. Sposito, G. (1984) The Surface Chemistry of Soils: Oxford University Press, New York, 234 pp.Google Scholar
  39. Sun, B. N. and Baronnet, A. (1989a) Hydrothermal growth of OH-phlogopite single crystals. I. Undoped growth medium: J. Crystal Growth 96, 265–276.CrossRefGoogle Scholar
  40. Sun, B. N. and Baronnet, A. (1989b) Hydrothermal growth of OH-phlogopite single crystals. II. Role of Cr and Ti adsorption on crystal growth rater: Chem. Geol. 78, 301–314.CrossRefGoogle Scholar
  41. Swartzen-Allen, S. L. and Matijevic, E. (1974) Surface and colloid chemistry of clays: Chem. Rev. 74, 385–400.CrossRefGoogle Scholar
  42. Torrie, G. M. and Valleau, J. P. (1980) Electrical double layers. I. Monte Carlo study of a uniformly charged surface: J. Chem. Phys. 73, 5807–5816.CrossRefGoogle Scholar
  43. Van Olphen, H. (1977) An Introduction to Clay Colloid Chemistry, 2nd ed.: Wiley, New York.Google Scholar
  44. Van Santen, R. A. (1982) Chemical-bonding aspects of heterogeneous catalysis. II. Solid acids: J. Roy. Neth. Chem. Soc. 101, 157–163.Google Scholar
  45. White, G. N., and Zelazny, L. (1988) Analysis and implications of the edge structure of dioctahedral phyllosilicates: Clays & Clay Minerals 36, 141–146.CrossRefGoogle Scholar
  46. Ziolkowski, J. (1986) Crystallochemical model of active sites on oxide catalysis: J. Catal. 100, 45–58.CrossRefGoogle Scholar
  47. Ziolkowski, J., and Dziembaj, L. (1985) Empirical relationship between individual cation-oxygen bond-length and bond energy in crystals and in molecules: J. Solid State Chem. 57, 291–299.CrossRefGoogle Scholar

Copyright information

© The Clay Minerals Society 1993

Authors and Affiliations

  • William F. Bleam
    • 1
  • Gereon J. Welhouse
    • 1
  • Mark A. Janowiak
    • 1
  1. 1.Department of Soil ScienceUniversity of Wisconsin-MadisonMadisonUSA

Personalised recommendations