Hostname: page-component-76d6cb85b7-kcxw8 Total loading time: 0 Render date: 2026-07-12T03:39:43.227Z Has data issue: false hasContentIssue false
  • English
  • Français

The Mechanism of Dehydration of Mg-Vermiculite

Published online by Cambridge University Press:  01 January 2024

G. F. Walker
G. F. Walker*
Affiliation:
Division of Industrial Chemistry, C. S. I. R. O., Melbourne, Australia
Get access Rights & Permissions [Opens in a new window]

Abstract

The hydrated Mg-vermiculite lattice contains double sheets of water molecules interleaved with silicate layers. In the fully hydrated condition, each water sheet is arranged in a regular hexagonal pattern and the interlayer cations are located midway between water sheets in octahedral coordination.

Release of water molecules from interlayer positions leads at first to a gradual contraction of the basal spacing from 14.81 A, during which the water network becomes increasingly distorted. The contraction ceases temporarily at 14.36 A while further water is withdrawn. When the probability that a cation has a complete octahedral “shell” of water molecules at a given instant falls below a certain value, an abrupt contraction to 13.82 A takes place during which the cations are displaced to sites near the silicate layer surfaces.

Release of further water causes a contraction to a lattice (11.59 A) in which single sheets of water molecules are interleaved with the silicate layers. The 11.59 A phase is stable until only a small proportion of the interlayer water remains, when an approximately regular interstratification of 11.59 A and 9.02 A (dehydrated) layers develops. The final traces of interlayer water are retained in the interior of the crystal with great tenacity owing to the sealing of the crystal near the edges.

Information

Type
Article
Information
Clays and Clay Minerals (National Conference on Clays and Clay Minerals) , Volume 4 , February 1955 , pp. 101 - 115
Copyright
Copyright © The Clay Minerals Society 1955

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Barshad, Isaac, 1948, Vermiculite and its relation to biotite as revealed by base-exchange reactions, x-ray analyses, differential thermal curves, and water content: Amer. Min., v. 33, p. 655–678.Google Scholar
Bradley, W. F., 1950, The alternating layer sequence of rectorite: Amer. Min., v. 35, p. 590–595.Google Scholar
Brindley, G. W., 1956, Allevardite, a swelling double-layer mica mineral: Amer. Min., v. 41, p. 91–103.Google Scholar
Caillère, S., Mathieu-Sicaud, A., and Hénin, S., 1950, New attempts to identify the mineral allevardite: Soc. Franc. Min. Bull., v. 73, p. 193–201.Google Scholar
Hendricks, S. B., Nelson, R. A., and Alexander, L. T., 1940, Hydration mechanism of the clay mineral montmorillonite saturated with various cations: J. Amer. Chem. Soc., v. 62, p. 1457–1464.CrossRefGoogle Scholar
Hendricks, S. B., and Teller, E., 1942, X-ray interference in partially ordered layer lattices: J. Chem. Phys., v. 10, p. 147–167.CrossRefGoogle Scholar
Mathieson, A. McL., and Walker, G. F., 1954, Crystal structure of magnesium-vermiculite: Amer. Min., v. 39, p. 231–255.Google Scholar
Norrish, K., and Quirk, J. P., 1954, The crystalline swelling of montmorillonite: Nature, v. 173, p. 255–256.CrossRefGoogle Scholar
Norrish, K., 1954, The manner of the swelling of montmorillonite: Nature, v. 173, p. 256–257; Faraday Soc. Disc., v. 18, p. 120-134.CrossRefGoogle Scholar
Wadsley, A. D., 1955, The crystal chemistry of non-stoichiometric compounds: Rev. Pure and Appl. Chem., v. 5, p. 165–193.Google Scholar
Walker, G. F., 1956, The diffusion of the interlayer water in vermiculite: Nature, v. 177, p. 239–240.CrossRefGoogle Scholar
Walker, G. F., and Cole, W. F., 1956, The vermiculites: in The differential thermal investigation of clays, Mackenzie, R. C., ed.; Mineralogical Soc., London.Google Scholar
Walker, G. F., and Milne, A. A., 1950, Hydration of vermiculite saturated with various cations: Trans. 4th Intern. Congr. Soil Sci., v. 2, p. 62–67.Google Scholar
Weiss, A. von, and Hofmann, U., 1951, Batavite: Zeits. f. Naturforsch., ν. 6b, no. 8, p. 405–409.Google Scholar