X-ray and temperature polarized Raman spectroscopic characterization of the LiNa3(SO4)2·6H2O crystal

✍ Scribed by J. Mendes-Filho; R. O. Paiva; P. T. C. Freire; F. E. A. Melo; I. Guedes; J. M. Sasaki; E. E. Castellano; J. Zukerman-Schpector

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 128 KB
• Volume: 30
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/(sici)1097-4555(199904)30:4<289::aid-jrs375>3.0.co;2-f

✦ Synopsis

Results of x-ray diffraction and polarized Raman studies of hexahydrated lithium sodium sulfate, LiNa 3 (SO 4 ) 2 Ð6H 2 O (LNSW), are reported. X-ray diffraction data show that at room temperature LNSW has a trigonal structure belonging to space group C 6 3v with six molecules per unit cell. Temperature-dependent first-order Raman light studies in the range 12-300 K were carried out in order to investigate the phonon spectra of LNSW in relation to the phase transition in the crystal. Complete spectra were obtained for geometries allowing the observation of A 1 and E species. Careful analysis of the spectra shows that the observed Raman modes do not exhibit variations in either wavenumber or intensity, or both, with temperature of the crystal, indicating that the C 6 3v phase at 300 K does not undergo a transition in the temperature range investigated. Data from Raman measurements taken at 12 K were used to propose an assignment of the fundamental modes on the basis of water group vibrations and correlations with previous data reported for other crystals belonging to the double sulfate family.