NMR study of cation motions in ferroic [C(NH2)(3)](3)Bi-2 Br-9

Authors
Grottel, M Pajak, Z Jakubas, R
Citation
M. Grottel et al., NMR study of cation motions in ferroic [C(NH2)(3)](3)Bi-2 Br-9, Z NATURFO A, 55(6-7), 2000, pp. 570-574
Citations number
19
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES
ISSN journal
09320784 → ACNP
Volume
55
Issue
6-7
Year of publication
2000
Pages
570 - 574
Database
ISI
SICI code
0932-0784(200006/07)55:6-7<570:NSOCMI>2.0.ZU;2-8
Abstract
The proton NMR second moment and spin-lattice relaxation time of polycrysta lline [C(NH2)(3)](3)Bi2Br9 were studied in a wide-temperature range. Dynami cal inequivalence of two crystallographically different guanidinium cations has been revealed. The C-3 reorientation of the two types of cations was f ound to be hindered by different potential barriers (25.1 kJ/mol and 34.7 k J/mol). At higher temperatures an overall reorientation of the cations was revealed. The existence and order-disorder character of the phase transitio ns at 333, 350, 415, and 425 K have been confirmed.