Conductivity measurements on liquid sulphur

The electrical conductivity of liquid sulphur has been measured from the melting point to 900° C, evaporation of the sulphur being prevented by use of an atmosphere of argon at elevated pressure. With rise in temperature, the conductivity increases except at the polymerization maximum near 170° C where a minimum in the conductivity is confirmed. Above 400° C the plot of log versus 1/T is linear, and on the assumption that the conductivity at these temperatures is intrinsic, a value of 3.1 eV is obtained for the energy gap. Although the rise in conductivity above 400° C is accompanied by a decrease in mean chain length in the liquid, there is no simple relationship between the two properties. The behaviour of sulphur is compared with that of liquid selenium.