Thermal, dielectric properties and vibrational spectra of [n-C4H9NH3]2[BiBr5] crystal

✍ Scribed by J. Tarasiewicz; R. Jakubas; J. Baran; A. Pietraszko

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 744 KB
• Volume: 792-793
• Category: Article
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2005.11.046

✦ Synopsis

n-C 4 H 9 NH 3 ] 2 [BiBr 5 ] exhibits five solid-solid structural phase transitions; at 309 (1st order), 291 (1st), 240 (1st), 219 (close to 2nd) and at 166 K (1st). The phase transitions at 291 and 240 K are accompanied by distinct dielectric anomalies. The dielectric relaxation process was found to appear over the phases (III) and (I). The infrared spectra for [n-C 4 H 9 NH 3 ] 2 [BiBr 5 ] were measured in the region of the internal vibration of the nbutylammonium cation (4000-400 cm K1 ) between 12 and 320 K. The temperature changes of wavenumbers and of a width for many of the internal modes of the n-butylammonium clearly indicate the contribution of the organic sublattice to the phase transition mechanism.