Phase transition of pyridinium tetrachloroiodate(III), PyHICl4, studied by a single crystal X-ray analysis and dielectric and heat capacity measurements
✍ Scribed by Tetsuo Asaji; Kazuo Eda; Hiroki Fujimori; Toshinobu Adachi; Takayoshi Shibusawa; Masaharu Oguni
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 327 KB
- Volume
- 826
- Category
- Article
- ISSN
- 0022-2860
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✦ Synopsis
Change of a local environment of a polar pyridinium ion, which is associated with the phase transition of crystalline pyridinium tetrachloroiodate(III) at T c = 217 K, was investigated by a single crystal X-ray analysis and dielectric and heat capacity measurements. The site symmetry 2/m of the ion at T > T c indicates an orientational disorder in the high-temperature phase (HTP). The energy difference DE between the stable and meta-stable orientations of the pyridinium ion at the 2/m site was estimated to be DE/R 6 560 K at 280 K in the HTP. Below the T c , an antiferroelectric ordering of the ions was revealed.