The role of the coordination defect (CD) in the structures of anion-deficient, fluorite-related compounds

D J M Bevan, Lisandra Lorraine Martin, Raymond Leslie Martin

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2 Citations (Scopus)


The various superstructure phases that occur with the anion-deficient compositions of binary oxides MO2-x with the fluorite structure as parent are explored here in terms of the original 'coordination defect' (or CD) concept in which each vacant oxygen site, □, is 'coordinated' by six O atoms thereby creating the octahedral 'structure-determining' entity [M 3.5□O6]. It emerges that the structure and composition of each anion-deficient (polymorph) phase can be described in terms of crystallographic 'motifs' which comprise sets of parallel coplanar polygons based on 210F and 111F CD linkages.

Original languageEnglish
Pages (from-to)17-29
Number of pages13
JournalActa Crystallographica Section B: Structural Science, Crystal Engineering and Materials
Issue number1
Publication statusPublished - Feb 2013


  • binary oxides
  • coordination defect concept
  • superstructure phases

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