Raman and infrared spectroscopic study of boussingaultite and nickelboussingaultite
Abstract
The Raman and infrared spectra of two secondary sulphate minerals, boussingaultite [(NH 4) 2Mg(SO 4) 2·6H 2O] and nickelboussingaultite [(NH 4) 2Ni,Mg(SO 4) 2·6H 2O] have been collected. Two bands observed at 983 and 990 cm -1 were attributed to the ν1(SO 42-) symmetric stretching vibration. The bands at 1133, 1096 and 1063 cm -1 in boussingaultite spectra and bands at 1149, 1093 and 1063 cm -1 in nickelboussingaultite spectra were attributed to the ν3(SO 42-) antisymmetric stretching vibration. The splitting of the ν4(SO 42-) bending vibration produced bands at 625 and 615 cm -1 in the boussingaultite spectra and 652, 624 and 602 cm -1 in the nickelboussingaultite spectra. Similarly, in the case of the ν2(SO 4) bending vibration, the bands were observed at 454 cm -1 in the boussingaultite spectra and 482, 457 and 440 cm -1 in the nickelboussingaultite spectra. The splitting of bands is the result of lowered symmetry of sulphate ions and possibly a result of substitution of Mg ions by Ni ions in nickelboussingaultite. The bands in the NH 4+ bending vibration region were observed at 1705 and 1678 cm -1 ( ν2), 1460 and 1438 cm -1 ( ν4) for the mineral boussingaultite. In the high wavenumber region the bands arising from the OH (bands above 3000 cm -1) and the NH 4+ (2940, 2918 and 2845 cm -1) stretching vibrations were identified.
- Publication:
-
Spectrochimica Acta Part A: Molecular Spectroscopy
- Pub Date:
- August 2009
- DOI:
- 10.1016/j.saa.2008.10.026
- Bibcode:
- 2009AcSpA..73..420C