121Sb Mossbauer study of Sb2S3-As2S3-Tl2S glasses

The local environment of antimony atoms in vitreous samples of the ternary system Sb2S3-As2S3-Tl2S is studied by Sb-121 Mossbauer spectroscopy. The results have been interpreted by means of EBV (empirical bond valence) and EBLV (empirical bond length valence) calculations, Variations in isomer shifts are attributed to changes in the environment of antimony atoms, The isomer shift is found to be a very sensitive parameter reflecting variations in the mean coordination number and in the mean Sb-S bond length, The results presented here confirm the random substitution of As by Sb in the binary system As2S3-Sb2S3 and the competitive effects-breaking of As-S-As bridges by Tl and formation of As-S-Sb bridges-in the ternary system Sb2S3-As2S3-Tl2S, in agreement with previous XAFS studies. (C) 1997 Academic Press.