Vapor Pressure of Bismuth

摘要

The total vapor pressure of bismuth as determined in the temperature range 1196deg;mdash;1268deg;K by the quasistatic and boilinghyphen;point methods is represented by logp(torr) = minus; (9150.3/T)+7.6327. The bismuth vapor density as found by the transpiration method is 3.05times;10minus;3g/liter at 1173deg;K. A combination of the pressure and density data yields an average molecular weight of the vapor at 1173deg;K of 328 which implies 57 mole Bi2and 43 mole Bi in the vapor, and partial pressures of 0.29 and 0.39 torr for the monatomic and diatomic species, respectively. The standard enthalpies of dissociation of Bi2(g) and of vaporization of liquid to monatomic and diatomic species are 47.8, 50.3, and 52.8 kcal/mole, respectively. The results are compared with those of other workers.