Electron spin resonance studies of halloysites.
Absorption lines in the g approx 4 region of ESR spectra of three New Zealand halloysites were found to originate from similar paramagnetic centres to those in kaolinites. Resonances in the g approx 4 region were not common to all the halloysites, although the signal at g = 2.0 for the Matauri Bay h...
Saved in:
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Published: |
2018
|
| Subjects: | |
| Online Access: | https://repository.li.mahidol.ac.th/handle/123456789/15335 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Mahidol University |
| Summary: | Absorption lines in the g approx 4 region of ESR spectra of three New Zealand halloysites were found to originate from similar paramagnetic centres to those in kaolinites. Resonances in the g approx 4 region were not common to all the halloysites, although the signal at g = 2.0 for the Matauri Bay halloysite is probably due to a trapped positive hole or trapped 018O - 2 ion. A 6- line resonance produced by Te Puke halloysite and removable by Na-saturation is attributed to exchangeable Mn on the clay surface. Low-T lines exhibited by all samples are due to V 4+ or VO 2+ replacing Al 3+ in the octahedral sheet. -D.J.M. |
|---|