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On the Chemistry of Clay
Author(s) -
Hofmann U.
Publication year - 1968
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.196806811
Subject(s) - montmorillonite , vermiculite , kaolinite , clay minerals , halloysite , silicate , illite , chlorite , mineral , silicate minerals , geochemistry , mica , geology , mineralogy , chemical engineering , inclusion (mineral) , chemistry , organic chemistry , paleontology , quartz , engineering
Kaolinite, illite, chlorite, montmorillonite, and vermiculite are among the most important of the clay minerals. Cations are embedded between the silicate layers and on the basal faces of the crystals. Whereas only the cations on the outer faces are exchangeable in the first three of the above minerals, those between the layers can also be replaced by others in montmorillonite and vermiculite. These characteristics and the ability of montmorillonite and vermiculite to undergo intracrystalline swelling and to form inclusion compounds are responsible for the industrial importance of kaolin and clay. The structure of halloysite is particularly interesting, since the silicate layers in this case are rolled up to form tabes. The possible role of the clay minerals as catalysts in the formation of petroleum and in the beginning of life is finally discussed.