Tolerance Factor and Cation–Anion Orbital Interactions Differentiating the Polar and Antiferrodistortive Structures of Perovskite Oxides ABO312. Issue 6 (16th April 2015)

• Record Type: Journal Article
• Authors: Whangbo, Myung‐Hwan; Gordon, Elijah E.; Bettis, Jerry L.; Bussmann‐Holder, Annette; Köhler, Jürgen
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 641:Issue 6(2015)
• Page Start: 1043
• Page End: 1052
• Publication Date: 2015-04-16
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.201500058
• Languages: English
• ISSNs: 0044-2313

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>We explored under what conditions perovskite oxides ABO₃ adopt a polar or an antiferrodistortive structure from the viewpoint of the tolerance factor τ and the orbital interactions of the empty orbitals of the <italic>A</italic> and <italic>B</italic> cations with the filled orbitals of their surrounding O^2– ions. Polar structures require the presence of a substantial size‐mismatch as well as strong cation‐anion orbital interactions at <italic>A</italic> or <italic>B</italic> cation sites. A tetragonal polar structure is preferred when the <italic>A</italic> cation empty orbitals are extended or when the B‐cation empty orbitals are contracted. A trigonal polar structure is favored in opposite cases. An antiferrodistortive structure is found for perovskites with weak size‐mismatch or those with substantial size‐mismatch if both <italic>A</italic> and <italic>B</italic> cations do not generate strong cation‐anion orbital interactions. Antiferrodistortive structures result from interactions involving the <italic>A</italic> cations with the O₄ squares of the face‐sharing <italic>A</italic>O₈ square‐prisms in a two‐in‐two‐out manner, and are found only when the A/O cation‐anion interactions are substantial.</p> </abstract>