Thermal expansion, compressibility, and local structure of fluorides and oxyfluorides with the rhenium trioxide structure
Morelock, Cody Reeves
MetadataShow full item record
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.