Superconducting Sr2-xAxCuO2F2+δ (A = Ca, Ba): Synthetic pathways and associated structural rearrangements

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External organisations

  • School of Chemistry
  • Andrews University
  • University of Birmingham
  • School of Physics and Space Research


The low-temperature fluorination of a range of insulating alkaline earth cuprates Sr2-xAxCuO3 (A = Ca (0 ≤ x ≤ 2); A = Ba (0 ≤ x ≤ 0.6)) can result in superconducting oxide fluorides Sr2-xAxCuO2F2+δ. In contrast, conventional high-temperature solid-state reactions produce thermodynamically more stable mixtures of oxides and fluorides. Various soft-chemistry fluorination pathways (utilizing F2 gas, NH4F, MF2 [M = Cu, Zn, Ni, Ag]) are compared with respect to their efficacy and mechanisms. Attention is also focused on the structural features of the mixed-oxide precursor and the final-oxide fluorides to highlight the remarkable structural rearrangements that occur during the low-temperature fluorination. The effects of fluorination of other Sr-Cu-O systems are used to identify the structural requirements of the precursor oxide in order to achieve such transformations.


Original languageEnglish
Pages (from-to)17-27
Number of pages11
JournalJournal of Solid State Chemistry
Issue number1
Publication statusPublished - 1 Jan 1998