Raman spectroscopic study of the antimonate mineral lewisite (Ca,Fe, Na)2(Sb,Ti)2O6(O,OH)7 |
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Authors: | Silmarilly Bahfenne |
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Affiliation: | Inorganic Materials Research Program, School of Physical and Chemical Sciences , Queensland University of Technology , GPO Box 2434, Brisbane, Queensland, 4001, Australia |
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Abstract: | The mineral lewisite, (Ca, Fe, Na)2(Sb, Ti)2O6(O, OH)7, an antimony-bearing mineral, has been studied by Raman spectroscopy. A comparison is made with the Raman spectra of other minerals, including bindheimite, stibiconite, and roméite. The mineral lewisite is characterised by an intense sharp band at 517 cm?1 with a shoulder at 507 cm?1 assigned to SbO stretching modes. Raman bands of medium intensity for lewisite are observed at 300, 356, and 400 cm?1. These bands are attributed to OSbO bending vibrations. Raman bands in the OH stretching region are observed at 3200, 3328, 3471 cm?1, with a distinct shoulder at 3542 cm?1. The latter is assigned to the stretching vibration of OH units. The first three bands are attributed to water stretching vibrations. The observation of bands in the 3200–3500 cm?1 region suggests that water is involved in the lewisite structure. If this is the case then the formula may be better written as (Ca, Fe2+, Na)2(Sb, Ti)2(O, OH)7 xH2O. |
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Keywords: | antimonite lewisite bindheimite bahianite Raman spectroscopy valentinite |
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