Raman spectroscopic investigation on Jarosite-Yavapaiite stability

The stability of synthetic Jarosite (KFe3(SO4)(2)(OH)(6)) at low temperature and reduced atmospheric pressure has been Studied by Raman spectroscopy. Jarosite remains stable between 8 and 295 K. provided that the sample is not exposed to reduced atmospheric pressure. When exposed to reduced atmospheric pressure (2.0 x 10(-2) Tort), however, the conversion of Jarosite into a different mineral is readily detected at room temperature by the appearance of a new Raman peak. The Raman shift of this peak (1032 cm(-1)) matches with that of Yavapaiite (KFe(SO4)(2)), which can be obtained by thermal decomposition of Jarosite above 473 K. These Studies provide a better understanding of the stability of Jarosite subjected to conditions similar to that on the surface of Mars. (C) 2009 Elsevier B.V. All rights reserved.