Pressure-induced disordering in α-SrZrF₆: Implications for the role of the countercation in glassy SrZrF₆

Reversible pressure-induced changes in the Raman and x-ray scattering of α-SrZrF₆ are reported. Above a pressure of ∼10.0 GPa there is a precipitous decline in the Raman intensity; this is a phenomenon associated with the formation of an amorphous state. Energy dispersive x-ray diffraction (EDXD) measurements show that the amorphization is not complete - some residual ordering persists. The results suggest that glassy SrZrF₆, prepared at ambient pressure, (1) contains kinked chains of ZrF₈ dodecahedra and (2) the medium range order of the glass is determined by the way ZrF ₈ units are arranged around the strontium countercation.