High‐temperature monoclinic α‐SrHfF 6 6 , and isostructural α‐SrZrF 6 6 : associating Hf 2 2 F 12 12 bipolyhedra and SrF 8 8 snub disphenoids

摘要

The structure of the high‐temperature monoclinic variety α‐SrHfF 6 (strontium hafnium hexafluoride) [and of isostructural α‐SrZrF 6 (strontium zirconium hexafluoride)] associates Hf 2 F 12 bipolyhedra and SrF 8 snub disphenoids, forming zigzag twisted [SrF 6 ] n layers. The distribution of the Hf and Sr polyhedra forms a three‐dimensional framework which can be related to the family of anion‐excess ReO 3 ‐related superstructures. α‐SrHfF 6 corresponds to a new ABX 6 type and is compared to the other main families already described. A partial amorphization of this structure is observed in samples quenched from the melt.