Abstract
Examination of two volcanic and two precipitated allophanes by solid-state NMR, thermal analysis and X-ray powder diffraction shows three of the samples to contain structural features similar to both tubular imogolite and defect layer-lattice aluminosilicates such as kaolinite. The fourth allophane, a precipitated sample from New Zealand, had no imogolite-like features and contained tetrahedral as well as octahedral aluminum. The imogolite-like units in allophane are less stable thermally than tubular imogolite. The NMR spectra and their changes on heating can be accounted for by a structural model in which a two-sheet, kaolinite-like structure containing defects (holes in the tetrahedral sheet) is curved into a sphere in which imogolite-like orthosilicate units are anchored into the octahedral sheet and fit into the tetrahedral defects. Computer simulation shows that the model is crystallographically sound, and accounts for all the known facts, including the spherical morphology, the solid-state NMR spectra and the thermal dehydroxylation behavior of all except the New Zealand allophane, which is of a different structural type.
Similar content being viewed by others
References
Barron, P. F., Wilson, M. A., Campbell, A. S., and Frost, R. L. (1982) Detection of imogolite in soils using solid state 29Si NMR: Nature (Lond.) 299, 616–618.
Berezowski, R. M. and MacKenzie, K. J. D. (1985) Thermal reactions of allophane under applied electric fields: Thermochim. Acta 84, 111–122.
Brindley, G. W. and Fancher, D. (1970) Kaolinite defect structures; possible relation to allophanes: in Proc. Int. Clay Conf., Tokyo, 1969, Vol. 2, L. Heller, ed., Israel Univ. Press, Jerusalem, 29–34.
Brown, G. (1980) Associated minerals: in Crystal Structures of Clay Minerals and Their X-ray Identification, G. W. Brindley and G. Brown, eds., Mineralogical Society, London, p. 406.
Brown, I. W. M., MacKenzie, K. J. D., Bowden, M. E., and Meinhold, R. H. (1985) Outstanding problems in the kaolinite-mullite reaction sequence investigated by 29Si and 27Al solid-state nuclear magnetic resonance: II, High-temperature transformations of metakaolinite: J. Amer. Ceram. Soc. 68, 298–301.
Brown, I. W. M., MacKenzie, K. J. D., and Meinhold, R. H. (1987) The thermal reaction of montmorillonite studied by high-resolution solid state 29Si and 27A1 NMR: J. Mater. Sci. 22, 3265–3275.
Cameron, W. E. (1977) Composition and cell dimensions of mullite: Amer. Ceram. Soc. Bull. 56, 1003–1011.
Fripiat, J. J., Leonard, A., and Uytterhoeven, J. B. (1965) Structure and properties of amorphous silicoaluminas. II Lewis and Bronsted acid sites: J. Phys. Chem. 69, 3274–3279.
Goodman, B. A., Russell, J. D., Montez, B., Oldfield, E., and Kirkpatrick, R. J. (1985) Structural studies of imogolite and allophanes by aluminum-27 and silicon-29 nuclear magnetic resonance spectroscopy: Phys. Chem. Mineral. 12, 342–346.
Kirkpatrick, R. J., Kinsey, R. A., Smith, K. A., Henderson, D. M., and Oldfield, E. (1985) High resolution solid state sodium-23, aluminum-27 and silicon-29 nuclear magnetic resonance spectroscopic reconnaissance of alkali and plagioclase feldspars: Amer. Mineral. 70, 106–123.
Kitagawa, Y. (1974) Dehydration of allophane and its structural formula: Amer. Mineral. 59, 1094–1098.
Lippma, E., Magi, M., Samosan, A., Engelhardt, B., and Grimmer, A. R. (1980) Structural studies of silicates by solid state high resolution 29Si NMR: J. Amer. Chem. Soc. 102, 4889–4893.
MacKenzie, K. J. D. (1970) Thermal decomposition of Derbyshire allophane: Clay Miner. 8, 349–351.
MacKenzie, K. J. D., Brown, I. W. M., Meinhold, R. H., and Bowden, M. E. (1985a) Outstanding problems in the kaolinite-mullite reaction sequence investigated by 29Si and 27Al solid-state nuclear magnetic resonance: I, Metakaolinite: J. Amer. Ceram. Soc. 68, 293–297.
MacKenzie, K. J. D., Brown, I. W. M., Meinhold, R. H., and Bowden, M. E. (1985b) Thermal reactions of pyrophyllite studied by high-resolution solid-state 27A1 and 29Si nuclear magnetic resonance spectroscopy: J. Amer. Ceram. Soc. 68, 266–272.
MacKenzie, K.J.D. and Cardile, C.M. (1988) The structure and thermal reactions of natural iron-containing allophanes studied by 57Fe Mössbauer spectroscopy: Thermochim. Acta 130, 259–267.
MacKenzie, K. J. D., Bowden, M. E., Brown, I. W. M., and Meinhold, R. H. (1989) Structure and thermal transformations of imogolite studied by 29Si and 27A1 high-resolution solid-state nuclear magnetic resonance: Clays & Clay Minerals 37, 317–324.
Okada, K., Morikawa, H., Iwai, S., Ohira, Y., and Ossaka, J. (1975) A structure model of allophane: Clay Sci. 4, 291–303.
Parfitt, R. L., Furkert, R. J., and Henmi, T. (1980) Identification and structure of two types of allophane from volcanic ash soils and tephra: Clays & Clay Minerals 28, 328–334.
Shimizu, H., Watanabe, T., Masuda, A., Henmi, T., and Saito, H. (1985) Studies on allophane and imogolite structures using 29Si and 27Al MAS/NMR: Abst. Ann. Meeting Nihon-Chikyu Kagakukai, p. 262.
Udagawa, S., Nakada, T., and Nakahira, M. (1970). Molecular structure of allophane as revealed by its thermal transformation: in Proc. Int. Clay Conf., Tokyo, 1969, Vol. 1, L. Heller, ed., Israel Univ. Press, Jerusalem, 151–159.
Wada, K. (1967) A structural scheme of soil allophane: Amer. Mineral. 52, 690–708.
Wada, K. (1979) Structural formulas of allophanes: in Proc. 6th Int. Clay Conf., Oxford, 1978, M. M. Mortland and V. C. Farmer, eds., Elsevier, Amsterdam, 537–553.
Wada, K., Wilson, M. A., Kakuto, Y., and Wada, S.-I. (1988) Synthesis and characterization of a hollow spherical form of monolayer aluminosilicate. Clays & Clay Minerals 36, 11–18.
Wada, L. and Yoshinaga, N. (1968) The structure of “imogolite”: Amer. Mineral. 54, 50–71.
Wells, N., Childs, C. W., and Downes, C. J. (1977) Silica Springs, Tongariro National Park, New Zealand—Analyses of the spring water and characterization of the aluminosilicate deposit: Geochim. Cosmochim. Acta 41, 1497–1506.
Wilson, M. A., McCarthy, S. A., and Fredericks, P. M. (1986) Structure of poorly-ordered aluminosilicates: Clay Miner. 21, 879–897.
Wilson, M. A., Wada, K., Wada, S-I., and Kakuto, Y. (1988) Thermal transformations of synthetic allophane and imogolite as revealed by nuclear magnetic resonance: Clay Miner. 23, 175–190.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mackenzie, K.J.D., Bowden, M.E. & Meinhold, R.H. The Structure and Thermal Transformations of Allophanes Studied by 29Si and 27Al High Resolution Solid-State NMR. Clays Clay Miner. 39, 337–346 (1991). https://doi.org/10.1346/CCMN.1991.0390401
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1346/CCMN.1991.0390401