Sulfur - a new information on this seemingly well-known element

Melting of orthorhombic sulfur (alpha-S) was investigated using DSC and X-ray analysis. It was found that reversible transformation orthorhombic to triclinic modification precedes melting. DSC and Raman spectroscopy study indicate that so-called lambda-transition is reversible one and opening of S-8 rings and S-n formation seems not to be a predominant process at that transition. Viscosity glass transition of glassy sulfur prepared by rapid cooling of equilibrium melt in the temperature region of anomalous viscosity doesn't depend on melt temperature, but temperature dependence of undercooled melt viscosity (so-called fragility) does. When equilibrium temperature increases, undercooled melt becomes stronger, according to Angell's classification.