151. Multi-step structural phase transitions with novel symmetry breaking and inverse symmetry breaking characteristics in a [Ag4I6]2− cluster hybrid crystal
- Author
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Xue-Wei Pan, Wen-Long Liu, Wan-Wan Yao, Lei Sang, Lifeng Wang, Jin Zhang, Xiao-Ming Ren, and Xiao-Zu Wang
- Subjects
Phase transition ,Metals and Alloys ,General Chemistry ,Ferroelectricity ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystal ,Crystallography ,Phase (matter) ,Materials Chemistry ,Ceramics and Composites ,Cluster (physics) ,Plastic crystal ,Symmetry breaking ,Spectroscopy - Abstract
In this study, a multi-step phase transition hybrid composed of (Pr-dabco)2Ag4I6 clusters (Pr-dabco+ = 1-propyl-1,4-diazabicyclo[2.2.2]octan-1-ium) has been prepared and characterized by microanalysis, IR and UV-vis spectroscopy, TG and DSC techniques, etc. This hybrid is thermally stable up to ∼486 K with five phases in the temperature region below 486 K. The phase transition shows symmetry breaking (SB) character between phases II (space group P21/c) and III (space group Pa3[combining macron]), while inverse symmetry breaking (ISB) between phases II and I (space group Pbca), and it is rather exceptional for matter to exhibit simultaneously SB and ISB nature in two successive phase transitions. Most importantly, each phase transition is associated with a dielectric anomaly, and phase V appears to be a plastic crystal with extra high ac conductivity (>10-2 S cm-1). Our work opens up new avenues to find a multi-phase transition material in silver halide hybrids.
- Published
- 2020
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