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Published on: October 25, 2019
Titanium local structure in tektite probed by X-ray absorption fine structure spectroscopy.
Ling Wang1, Akira Yoshiasa, Maki Okube
1Graduate School of Science, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, Japan. wangling.1984@live.cn
Journal of Synchrotron Radiation
|October 15, 2011
Summary
Titanium in tektites exhibits diverse local structures, including four- and five-coordinated sites, unlike typical titanium minerals. These findings suggest structural changes may occur during impact events.
Area of Science:
- Geochemistry
- Materials Science
- Mineralogy
Background:
- Tektites are natural glasses formed during meteorite impacts.
- Understanding the local structure of elements in tektites provides insights into impact processes.
- Titanium's coordination in geological materials is sensitive to formation conditions.
Purpose of the Study:
- To quantitatively determine the local structure of titanium (Ti) in tektites.
- To investigate Ti-O distances and Ti coordination numbers.
- To classify tektite types based on titanium's local environment.
Main Methods:
- X-ray absorption near edge structure (XANES) spectroscopy at the Ti K-edge.
- Extended X-ray absorption fine structure (EXAFS) analysis.
- Analysis of Ti-O distances, coordination numbers, and radial distribution functions.
Main Results:
- Titanium in tektites exists in four-, five-, and six-coordinated sites.
- XANES spectra resemble high-temperature TiO(2)-SiO(2) glass and TiO(2) anatase.
- Ti-O distances vary with coordination number: 1.79-1.84 Å (4-fold), 1.89-1.92 Å (5-fold), and 1.96-2.00 Å (6-fold).
- All samples confirmed Ti valence as +4.
Conclusions:
- Tektites can contain titanium in four- and five-coordinated sites, deviating from common six-coordinated titanium minerals.
- The local structure of titanium in tektites is variable and may be influenced by impact events.
- This study provides quantitative data on titanium's local environment in tektites.
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