The Ti environment in natural hibonite: XANES spectroscopy and computer modelling

16th International Conference on X-ray Absorption Fine Structure

Kravtsova, Antonina N^1 ; Soldatov, Alexander V^1 ; Walker, Andrew M^2 ; Berry, Andrew J^3

International Research Center Smart Materials, Southern Federal University, 5 Sorge Street, Rostov-on-Don

344090, Russia^1

School of Earth and Environment, University of Leeds, Leeds

LS2 9JT, United Kingdom^2

Research School of Earth Sciences, Australian National University, Canberra

ACT

2601, Australia^3

关键词: Computer modelling;    Coupled substitution;    Experimental spectra;    Local atomic structures;    Low concentrations;    Structural modeling;    Structural models;    Theoretical spectra;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012089/pdf
DOI  :  10.1088/1742-6596/712/1/012089

来源: IOP

【 摘 要 】

The local atomic structure around Ti in Ti-bearing hibonite (CaAl12O19) was studied using X-ray absorption near-edge structure (XANES) spectroscopy and computer modelling. Structural models of the direct substitution of Al by Ti3+, Al by Ti4+charge balanced by the coupled substitution of Mg2+ for Al, and small Ti clusters were considered. The Ti K-XANES spectra of natural hibonite with different Ti concentration were recorded. Theoretical Ti K- XANES spectra for structural models of hibonite were calculated. It was shown that the theoretical Ti K-XANES spectra for a model with Ti at the five-coordinated M2 site are in agreement with the experimental XANES spectra of hibonite with low concentrations of Ti, while the theoretical spectra for a structural model of clustered Ti are in agreement with the experimental spectra of hibonite with higher Ti contents.