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An Above‐Room‐Temperature Phase Transition with Dielectric‐Switching Properties in a Halogenobismuthate(III) – Tris(Cyclohexylmethylammonium) Pentabromobismuthate(III) Bromide
Author(s) -
Yin Zi,
Gao JiXing,
Chen HaiPeng,
Liao WeiQiang
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700529
Subject(s) - monoclinic crystal system , differential scanning calorimetry , dielectric , chemistry , phase transition , crystallography , powder diffraction , phase (matter) , diffraction , transition temperature , crystal structure , condensed matter physics , materials science , optics , organic chemistry , thermodynamics , optoelectronics , physics , superconductivity
A one‐dimensional halogenobismuthate(III), [CMA] 3 · [BiBr 5 ] · [Br] ( 1 , CMA = cyclohexylmethylammonium), is discovered as a high‐temperature phase‐transition material with reversible and switchable dielectric behavior. Compound 1 undergoes a solid‐state phase transition at T C = 401.6 K, as confirmed by differential scanning calorimetry (DSC), variable‐temperature single‐crystal X‐ray diffraction, variable‐temperature powder X‐ray diffraction (PXRD), and dielectric measurements. Compound 1 crystalizes in the monoclinic space group P 2 1 / c in the room‐temperature phase (RTP). The asymmetric unit of 1 consists of three independent CMA cations, one isolated Br – anion, and one [BiBr 5 ] 2– anion, which extends along the c axis to form a one‐dimensional zigzag chain through corner‐sharing BiBr 6 octahedra. Interestingly, the temperature‐dependent dielectric constants display striking steplike dielectric anomalies with two distinct dielectric states below and above T C ; therefore, 1 could be conceived to be an appealing candidate for dielectric switches. It is believed that this finding might pave the way to the exploration and design of high‐temperature phase‐transition materials for practical applications.