A Raman spectroscopic study of the antimony mineral klebelsbergite Sb4O4(OH)2(SO4)

Many minerals based upon antimonite and antimonate anions remain to be studied. Most of the bands occur in the low wavenumber region, making the use of infrared spectroscopy difficult. This problem can be overcome by using Raman spectroscopy. The Raman spectra of the mineral klebelsbergite Sb4O4(OH)2(SO4) were studied and related to the structure of the mineral. The Raman band observed at 971 cm−1 and a series of overlapping bands are observed at 1029, 1074, 1089, 1139 and 1142 cm−1 are assigned to the SO42−ν1 symmetric and ν3 antisymmetric stretching modes, respectively. Two Raman bands are observed at 662 and 723 cm−1, which are assigned to the SbO ν3 antisymmetric and ν1 symmetric stretching modes, respectively. The intense Raman bands at 581, 604 and 611 cm−1 are assigned to the ν4 SO42− bending modes. Two overlapping bands at 481 and 489 cm−1 are assigned to the ν2 SO42− bending mode. Low-intensity bands at 410, 435 and 446 cm−1 may be attributed to OSbO bending modes. The Raman band at 3435 cm−1 is attributed to the OH stretching vibration of the OH units. Multiple Raman bands for both SO42− and SbO stretching vibrations support the concept of the non-equivalence of these units in the klebelsbergite structure. It is proposed that the two sulfate anions are distorted to different extents in the klebelsbergite structure. Copyright © 2010 John Wiley & Sons, Ltd.