An ESR study of kaolinite under extreme conditions

Kaolinite exhibits two principal ESR resonances centred at g∼4 and g∼2. Following heat treatment at 500°C, the low-field resonance collapses with a simultaneous increase in intensity of the central line. Similar results were obtained from dry-ground kaolinite and this change is attributed partly to...

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Bibliographic Details
Main Authors: N. Chaikum, R. M. Carr
Other Authors: Mahidol University
Format: Article
Published: 2018
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Online Access:https://repository.li.mahidol.ac.th/handle/123456789/15740
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Institution: Mahidol University
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Summary:Kaolinite exhibits two principal ESR resonances centred at g∼4 and g∼2. Following heat treatment at 500°C, the low-field resonance collapses with a simultaneous increase in intensity of the central line. Similar results were obtained from dry-ground kaolinite and this change is attributed partly to oxidation of Fe 2+ . X-irradiation resulted in new paramagnetic species on the clay surfaces and a corresponding intense signal at g=2, while treatment with solutions of a strong acid and a strong base produced no significant change in the spectrum. © 1989.