Controlling multiple orderings in metal thiocyanate molecular perovskites A x {Ni[Bi(SCN)6]}.
Chem Sci
; 12(10): 3516-3525, 2021 Jan 15.
Article
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| MEDLINE
| ID: mdl-34163625
We report four new A-site vacancy ordered thiocyanate double double perovskites, , A = K+, NH4 +, CH3(NH3)+ (MeNH3 +) and C(NH2)3 + (Gua+), including the first examples of thiocyanate perovskites containing organic A-site cations. We show, using a combination of X-ray and neutron diffraction, that the structure of these frameworks depends on the A-site cation, and that these frameworks possess complex vacancy-ordering patterns and cooperative octahedral tilts distinctly different from atomic perovskites. Density functional theory calculations uncover the energetic origin of these complex orders and allow us to propose a simple rule to predict favoured A-site cation orderings for a given tilt sequence. We use these insights, in combination with symmetry mode analyses, to show that these complex orders suggest a new route to non-centrosymmetric perovskites, and mean this family of materials could contain excellent candidates for piezo- and ferroelectric applications.
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01-internacional
Base de datos:
MEDLINE
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En
Revista:
Chem Sci
Año:
2021
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Article
Pais de publicación:
Reino Unido