Vibrational spectra and phase transition in Cd(CN)2·G clathrates [G = HCCl3, HCBr3, CH3CCl3, (CH3)3CCl or CHCl2CHCl2]

✍ Scribed by Isao Kanesaka; Yuki Kita; Shin-Ichi Nishikiori

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 128 KB
• Volume: 33
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.810

✦ Synopsis

Abstract

Vibrational spectra of Cd(CN)~2~·G clathrates were observed and changes in the spectral features with temperature analyzed, deducing phase transitions. A two‐step transition was found in the clathrates with G = HCCl~3~ (T~c~ = 188, 122 K), HCBr~3~ (249, 134 K) and CH~3~CCl~3~ (228, 154 K). The upper transition is ascribed to the ordering of the three‐site structure, pointing out similarity in the manner of interaction between the clathrates with C~3v~ and T~d~ guests. The lower transition is of a new type, which is considered to be an ordering process of dipoles. In Cd(CN)~2~·CHCl~2~CHCl~2~ a phase transition was found at 160 K. Its low transition temperature is ascribed to the difference in disordered structures between the C~3v~ and CHCl~2~CHCl~2~ systems. ^2^H NMR spectral features of Cd(CN)~2~·DCCl~3~ are reported. Copyright © 2002 John Wiley & Sons, Ltd.