Abstract

Synchrotron radiation was used to measure the EXAFS and XANES polarization dependences for intercalation compounds of graphite fluoride. An approach is developed which allows one to analyze the orientation of molecules of arbitrary shapes using XANES and EXAFS data. Analyzing the orientation dependences of BrK XANES spectra for the T-shaped BrF3 molecules, we determined possible combinations and admissible ranges of angles between the normal to the graphite fluoride matrix planes and the Br−F bond directions (α=52–90°, β=27–82°) and between the normal to the matrix planes and the molecular planes (γ=27–53°). The average orientation angles obtained by the combined analysis of the EXAFS and XANES data are as follows: α=62±1.5°, β=58±1.5°, γ=45±1.5°. The interatomic distances Br−F, Br−Br, and Fe−Br are determined. It is established that thermal treatment, which recovers the X-ray diffraction pattern from the unfilled matrix, does not affect the predominant orientation of the BrF3 molecules. This suggests that the thermally treated graphite fluoride matrix contains thin layers of ordered molecules. The absence of the polarization dependence of the spectra of FeBr3 in graphite fluoride allows the assumption that the molecular planes are oriented with respect to the normal to the matrix planes at a “magic” angle of 35°.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.