Non-integral hybrid ions in tourmaline: buffering and geo-thermometry
(2009) In European Journal of Mineralogy 21(1). p.241-250- Abstract
- The tourmaline group of minerals is indeed an enigma. Experimental data from optical spectroscopy, electron microscopy, and Mossbauer spectroscopy reveal a host of physical properties that lack a common structural clarification. For example, tourmaline samples change colour when irradiated with X-ray and gamma-ray radiations some reverting back when heated in air; exhibit simultaneous oxidation and reduction on annealing in an atmosphere of H-2; display different plane group symmetries under TEM; possess the most complicated Mossbauer spectra of all Fe-bearing silicates. In this study, four Brazilian samples were chosen for detailed study by Mossbauer spectroscopy to find out a common structural factor to the physical anomalies reported in... (More)
- The tourmaline group of minerals is indeed an enigma. Experimental data from optical spectroscopy, electron microscopy, and Mossbauer spectroscopy reveal a host of physical properties that lack a common structural clarification. For example, tourmaline samples change colour when irradiated with X-ray and gamma-ray radiations some reverting back when heated in air; exhibit simultaneous oxidation and reduction on annealing in an atmosphere of H-2; display different plane group symmetries under TEM; possess the most complicated Mossbauer spectra of all Fe-bearing silicates. In this study, four Brazilian samples were chosen for detailed study by Mossbauer spectroscopy to find out a common structural factor to the physical anomalies reported in the literature. It was found out that the tourmaline group of minerals contain multi-valence elements that are involved in electron exchange between the edge-sharing asymmetric Y and Z crystallographic sites. It is conceivable that the host of physical properties recorded in the literature could be due to the inherent structural misfit between the Y and Z sites and the mechanisms adopted to reduce the strain associated along the shared edges. The complexity of non-integral oxidation states possible - due to electron sharing among the different multi-valence elements present in the structure - further enhances the diverse physical properties observed. Moreover, on heating in air, no net oxidation or reduction takes place in the tourmaline group of minerals over a temperature range as long as there are electron donors and acceptors left in the structure, serving simultaneously as potential single-phase buffers and geo-thermometers. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1372509
- author
- Ferrow, Embaie LU
- organization
- publishing date
- 2009
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- hybrid ions, tourmaline, Mossbauer, buffer, geo-thermometer
- in
- European Journal of Mineralogy
- volume
- 21
- issue
- 1
- pages
- 241 - 250
- publisher
- Copernicus GmbH
- external identifiers
-
- wos:000263454400023
- scopus:78650202301
- ISSN
- 1617-4011
- DOI
- 10.1127/0935-1221/2009/0021-1863
- language
- English
- LU publication?
- yes
- id
- 378d0048-cb11-4c55-94dd-899836764666 (old id 1372509)
- date added to LUP
- 2016-04-01 12:20:38
- date last changed
- 2022-02-26 05:49:42
@article{378d0048-cb11-4c55-94dd-899836764666,
abstract = {{The tourmaline group of minerals is indeed an enigma. Experimental data from optical spectroscopy, electron microscopy, and Mossbauer spectroscopy reveal a host of physical properties that lack a common structural clarification. For example, tourmaline samples change colour when irradiated with X-ray and gamma-ray radiations some reverting back when heated in air; exhibit simultaneous oxidation and reduction on annealing in an atmosphere of H-2; display different plane group symmetries under TEM; possess the most complicated Mossbauer spectra of all Fe-bearing silicates. In this study, four Brazilian samples were chosen for detailed study by Mossbauer spectroscopy to find out a common structural factor to the physical anomalies reported in the literature. It was found out that the tourmaline group of minerals contain multi-valence elements that are involved in electron exchange between the edge-sharing asymmetric Y and Z crystallographic sites. It is conceivable that the host of physical properties recorded in the literature could be due to the inherent structural misfit between the Y and Z sites and the mechanisms adopted to reduce the strain associated along the shared edges. The complexity of non-integral oxidation states possible - due to electron sharing among the different multi-valence elements present in the structure - further enhances the diverse physical properties observed. Moreover, on heating in air, no net oxidation or reduction takes place in the tourmaline group of minerals over a temperature range as long as there are electron donors and acceptors left in the structure, serving simultaneously as potential single-phase buffers and geo-thermometers.}},
author = {{Ferrow, Embaie}},
issn = {{1617-4011}},
keywords = {{hybrid ions; tourmaline; Mossbauer; buffer; geo-thermometer}},
language = {{eng}},
number = {{1}},
pages = {{241--250}},
publisher = {{Copernicus GmbH}},
series = {{European Journal of Mineralogy}},
title = {{Non-integral hybrid ions in tourmaline: buffering and geo-thermometry}},
url = {{http://dx.doi.org/10.1127/0935-1221/2009/0021-1863}},
doi = {{10.1127/0935-1221/2009/0021-1863}},
volume = {{21}},
year = {{2009}},
}