Raman and infrared spectroscopic study of boussingaultite and nickelboussingaultite

The Raman and infrared spectra of two secondary sulphate minerals, boussingaultite [(NH(4))(2)Mg(SO(4))(2) x 6 H(2)O] and nickelboussingaultite [(NH(4))(2)Ni,Mg(SO(4))(2) x 6 H(2)O] have been collected. Two bands observed at 983 and 990 cm(-1) were attributed to the nu(1)(SO(4)(2-)) 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 nu(3)(SO(4)(2-)) antisymmetric stretching vibration. The splitting of the nu(4)(SO(4)(2-)) 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 nu(2)(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) (nu(2)), 1460 and 1438 cm(-1) (nu(4)) 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.