Raman spectroscopic investigations of some Tl-sulfosalt minerals containing pyramidal (As,Sb)S3 groups.

Oriented single crystals of stibioellisite (Tl3SbS3), parapierrotite (TlSb5S8), weissbergite (TlSbS2), and lorandite (TlAsS2) were investigated by polarized Raman spectroscopy. Whereas stibioellsite shows isolated SbS3 groups, the rest of the minerals show interconnected pyramidal (As,Sb)S3 groups. Raman bands of the investigated minerals occur between 400 and 10 cm-1. The internal vibrations for stibioellsite occur between 350-100 cm-1. Those of the interconnected pyramidal groups occur between 350 and 10 cm-1 in parapierrotite, 350 and 90 cm-1 in weissbergite, and 420 and 130 cm-1 in lorandite. Approximate similarities in the spectral features are evident when comparing the spectra of minerals containing XS3 pyramids with the spectra of the minerals in the present study. A clear distinction between Raman spectra of separated and interconnected SbS3 groups is not observed. [ABSTRACT FROM AUTHOR]