Abstract
The hydrated form of tubular halloysite [halloysite (10 Å)] was observed by a conventional electron microscope equipped with an environmental cell (E.C.), by which the “natural” form was revealed without dehydration of the interlayer water. This study mainly reports the selected area electron diffraction (SAED) analysis of the halloysite (10 Å) and its morphological changes by dehydration. The SAED pattern showed halloysite (10 Å) has two-layer periodicity in a monoclinic structure with the unit cell parameters of a = 5.14 Å, b = 8.90 Å, c = 20.7 Å, ² = 99.7°, in space group Cc, and almost the same structure as the dehydrated form of halloysite [halloysite (7 Å)]. This means that the dehydration of the interlayer water did not greatly change or affect the structure of halloysite (10 Å). Accompanying the dehydration of the interlayer water, there appeared along the halloysite tube axis clear stripes that were about 50–100 Å in width. The diameters of the tubular particles also increased about 10%. From the results of various experiments, such as a focussing series, observation of the surface structure by the replica method, observation of end-views of the tubular particles, and others, these two phenomena were explained as follows: Halloysite crystals have “domains” along the c-axis direction, the thicknesses of the “domains” vary ca. 50–100 Å. They are tightly connected with each other when the halloysite is hydrated, but are separated from each other by the dehydration of the interlayer water, whereupon the stripes come into existence along the tube axis. Taking these considerations into account, a model of dehydration is proposed. Moreover, a new method of calculating the β-angle is proposed in the Appendix.
Резюме
Гвдратная форма трубчатого галлуазита /галлуазит (10Å)/ исследовалась под обычном электронным микроскопом,снабженным микросетчатой камерой /М. K./,благодаря чему была выявлена “естественная” форма без дегидратации межслойной воды.Эта статья посвящена анализу методом электронной дифракции избранной зоны /ЭДИЗ/ галлуазита и его морфологических изменений в результате дегидратации.Рисунок ЭДИЗ показал,что галлуазит (10Å) имеет двухслойную периодичность в моноклинальной структуре с параметрами единичной ячейки а=5, 14Å, b=8,90Å, с=20, 7Å, 0=99,7° в пространственной группе Сс и почти такую же структуру,как обезвоженная форма галлуазита /галлуазит [7Å)/.Это означает, что дегидратация межслойной воды не изменяет и не воздействует значительно на структуру галлуазита (10Å).Впроцессе дегидратации межслойной воды вдоль осей трубок появились светлые полосы шириной около 50–100Å.Диаметры трубчатых частиц также увеличились примерно на 10%.В результате различных экспериментов,таких как серии фокусировок,наблюдение поверхностной структкры методом репродукции,наблюдение торцов трубчатых частиц и других, этот феномен объясняется следующим образом.Кристаллы галлуазита имеют “домены”,направленные вдоль о сей с,толщина “доменов” варьирует в педелах 50–100Å.Они тесно связаны друг с другом,когда галлуазит насыщен водой,но разделяются в результате дегидратации межслойной воды,и тогда появляются полосы вдоль осей трубок.Принимая во внимание эти соображения предлагается модель дегидратации.Более того,в приложении предлагается метод вычисления угла ².
Similar content being viewed by others
References
A.I.P.E.A. (1975) Meeting of the nomenclature committee of A.I.P.E.A. (in Mexico City): Clays & Clay Minerals 23, 413–414.
Askenasy, P.E., Dixon, J. B. and Mckee, T. R. (1973) Spheroidal halloysite in a Guatemalan soil: Soil Sci. Soc. Am. Proc. 37, 799–803.
Bailey, S. W. (1963) Polymorphism of the kaolin minerals: Am. Mineral. 48, 1196–1206.
Bates, T. F. (1971) The kaolin minerals. In The Electron-Optical Investigation of Clays (Edited by Gard, J. A.), pp. 109–157: Mineral. Soc., London.
Bates, T. F., Hildebrand, F. A. and Swineford, A. (1954) Morhpology and structure of endellite and halloysite: Am. Mineral. 35, 463–484.
Brindley, G. W. (1961) Kaolin, serpentine and kindred minerals. In The X-ray Identification and Crystal Structures of Clay Minerals (Edited by Brown, G.), pp. 51–131: Mineral. Soc., London.
Brindley, G. W. and Nakahira, M. (1958) Further consideration of the crystal structure of kaolinite: Mineral. Mag. 31, 781–786.
Brindley, G. W. and Robinson, K. (1946) The structure of kaolinite: Mineral. Mag. 27, 242–253.
Chukhrov, F. V. and Zvyagin, B. B. (1966) Halloysite, a crystallochemically and mineralogically distinct species: Proc. Int. Clay Conf, Jerusalem 1, 11–25.
Dixon, J. B. and Mckee, T. R. (1974) Internal and external morphology of tubular and spheroidal halloysite particles: Clays & Clay Minerals 22, 127–137.
Dorset, D. J. and Parsons, D. F. (1975) Electron diffraction from single, fully-hydrated, ox-liver catalase microcrystals: Acta Crystallogr. A31, 210–215.
Drits, V. A. and Kashaev, A. A. (1960) An X-ray study of a single crystal of kaolinite: Kristallografiya 5, 224–227 (Eng. transi, pp. 207–210).
Fukami, A. and Katoh, M. (1972) Construction and application of environmental cell: Proc. 30th EMSA Meeting, 614–615.
Fukami, A. and Murakami, S. (1974) Observation of hydrated materials using environmental cell and its application: Electron Microscopy 9, 4–19 (In Japanese).
Fukami, A., Fukushima, K. and Murakami, S. (1974) Observation technique of hydrated biological material using environmental cell: Proc. 8th Int. Congr. Electron Microscopy, Canberra, 2, 45–46.
Gard, J. A. (1971) Interpretation of electron micrographs and electron-diffraction patterns. In The Electron-Optical Investigation of Clays (Edited by Gard, J. A.), pp. 27–78: Mineral. Soc., London.
Honjo, G. and Mihama, K. (1954) A study of clay minerals by electron-diffraction diagrams due to individual crystallites: Acta Crystallogr. 7, 511–513.
Honjo, G., Kitamura, N. and Mihama, K. (1954) A study of clay minerals by means of single-crystal electron diffraction diagram—the structure of tubular kaolin: Clay Miner. Bull. 2, 133–141.
Iizuka, M. and Kobayashi, K. (1975) On the crystallite thickness and interlayer spacing in some kaolin minerals. In Contributions to Clay Mineralogy (Dedicated to Prof. T. Sudo, On the Occasion of His Retirement), pp. 23–25 (in Japanese with English abstract).
Nagasawa, K., Takeshi, H., Fujii, N. and Hachisuka, E. (1969) Occurrence, properties and uses of the clays and allied minerals in Japan—Kaolin minerals (Edited by Editorial Subcommittee for “The Clays of Japan” Organizing Committee 1969 International Clay Conference in Tokyo), pp. 17–70. Geological Survey of Japan, Tokyo.
Newnham, R. E. (1961) A refinement of the dickite structure and some remarks of polymorphism in kaolin minerals: Mineral. Mag. 32, 683–704.
Newnham, R. E. and Brindley, G. W. (1966) The crystal structure of dickite: Acta Crystallogr. 9, 759–764.
Parsons, D. F. (1974) Structure of wet species in electron microscopy: Science 186, 407–414.
Souza Santos, P. de, Brindley, G. W. and Souza Santos, H. de (1965) Mineralogical studies of kaolinite—halloysite clays: Part III. A fibrous kaolin mineral from Piedade, São Paulo, Brazil: Am. Mineral. 50, 619–628.
Sudo, T. and Ossaka, J. (1952) Hydrated halloysite from Japan: Jpn. J. Geol. Geogr. 22, 215–229.
Zvyagin, B. B. (1960) Electron-diffraction determination of the structure of kaolinite: Kristallografiya 5, 40–50 (Engl, transi, pp. 32–42).
Zvyagin, B. B. (1967) Electron-diffraction Analysis of Clay Mineral Structure (Revised Edition): Plenum Press, New York.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kohyama, N., Fukushima, K. & Fukami, A. Observation of the Hydrated form of Tubular Halloysite by An Electron Microscope Equipped with An Environmental Cell. Clays Clay Miner. 26, 25–40 (1978). https://doi.org/10.1346/CCMN.1978.0260103
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1346/CCMN.1978.0260103