Vapour Pressure Equations and Melting Points of Allotropes of Sulphur and the α–γ Transition Point

Abstract

RECENT measurements of the vapour pressures of sulphur allotropes¹ and of their low-temperature solubilities² indicate that a transition point exists between β- and γ-sulphur at about −88.5° C. It is well known that a further transition point exists between α- and β-sulphur at 95.5° C. Since there is some evidence that the solubility of γ-sulphur may become less than the solubility of α-sulphur in petroleum ether at very low temperatures², it seemed desirable to examine the existing data on the vapour pressures of sulphur allotropes to see if any prediction could be made about the existence of an α–γ transition point.