Identification des allotropes S6 et S7 du soufre dans le trophosome du vestimentifère Riftia pachyptila

Abstract The two sulphur allotropes S 6 and S 7 were characterised by gas chromatography/mass spectrometry coupling experiments in trophosomes of Riftia pachyptila (Vestimentifera), which inhabit hydrothermal vents. Both allotropes (approximately 3% for both) are associated with the usual form S 8 that represents about 97% of the total sulphur fraction. These new natural varieties of sulphur could be due to bacterial oxidation of hydrogen sulphide in extreme conditions (about 300 kg cm –2 ). However, the occurrence of the same allotropes in mineral sulphur from different origin, terrestrial and extraterrestrial as well, could indicate that natural sulphur is a mixture of these three allotropes, with proportions depending on its geographical origin.