Octahedral tilting in Prussian blue analogues

• Octahedral tilting is key to the structure and functionality of perovskites. We present a metastudy of published literature showing how these distortions manifest in the related Prussian blue analogues (PBAs): cyanide versions of double perovskites with formula AM[M '(CN)(6)](1-y)(y)center dot nH(2)O (A = alkali metal, M and M ' = transition metals, = vacancy/defect). Tilts are favoured by high values of x if A = Na or K, whereas the transition metals play a less important role. External hydrostatic pressure induces tilt transitions nearly irrespective of the stoichiometry, whereas thermal transitions are only reported for x > 1. Interstitial water can alter the transitions induced by a different stimulus, but (de)hydration per se does not lead to tilts. Finally, the implications for rational design of critical functionality-including improper ferroelectricity and electrochemical performance-are discussed. The results are integral for a fundamental understanding of phase transitions and for the development of functional materials based on PBAs.

Subject headings

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

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art (subject category)