Some physical properties of gas-freed sulphur

Abstract

In a paper by the authors on the viscosity of liquid sulphur, it was shown how difficult it is to prepare a sample of sulphur whose viscosity is independent of previous heat treatment. This uncertainty extends to all the physical pro­perties of sulphur and is noted in papers by Kellas and by Smith and his co-workers. Smith regards liquid sulphur as consisting of two modifications S λ and S µ , the proportion of S µ to S λ increasing as the temperature is raised, with a marked increase in the neighbourhood of 160°C. The presence, however, of such products as SO 2 , traces of H 2 SO 4 , and H 2 S exerts a considerable retarding influence on the attainment of inner equilibrium between these two varieties, thus causing a great variation in the physical properties at any given temperature. Between the temperatures 160°C. and 180°C. the viscosity increases several thousand times. With sulphur purified in the ordinary way, by simple distilla­tions or precipitations, remarkable variations in the viscosity are possible over this range of temperature. This property, therefore, provides an exceptionally sensitive test of the dependence of the sulphur on previous-treatent, and a sample, whose viscosity was definite and constant at any temperature, would almost certainly be definite in its other physical properties.