Thermal expansion, compressibility, and local structure of fluorides and oxyfluorides with the rhenium trioxide structure

Thermal expansion;Local structure;X-ray diffraction;Fluorides;Oxyfluorides;Synchrotron diffraction

Morelock, Cody Reeves ; Wilkinson, Angus P. Chemistry and Biochemistry Jones, Christopher W. Perry, Joseph W. White, Mary A. Zhang, Z. J. ; Wilkinson, Angus P.

University:Georgia Institute of Technology

Department:Chemistry and Biochemistry

关键词: Thermal expansion;    Local structure;    X-ray diffraction;    Fluorides;    Oxyfluorides;    Synchrotron diffraction;   

Others  :  https://smartech.gatech.edu/bitstream/1853/53000/1/MORELOCK-DISSERTATION-2014.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

The simple cubic ReO₃-type framework has all of the key features required for negative thermal expansion (NTE) arising from the transverse thermal motion of bridging atoms and rotation of rigid polyhedra. Although ReO₃ itself only displays low NTE below ambient temperature, there is a potentially large family of isostructural fluorides and oxyfluorides that could display NTE. However, the coefficients of thermal expansion (CTE) of ReO₃-type materials range from strongly positive to strongly negative. Through extensive use of in situ synchrotron diffraction, this thesis examines the thermal expansion of several ReO₃-type fluorides and oxyfluorides, demonstrating the effects on CTE and related properties of both cation and anion substitution and the disorder produced by these structural changes.