Abstract
The vapor pressures and heats of sublimation of ruthenium and osmium have been measured using a microbalance technique based on the Langmuir method. Heats of sublimation at 298 °K were calculated with the aid of free energy functions. Least squares lines for the vapor pressure data, heats of sublimation, and normal boiling points were obtained as follows : Ruthenium: Log Patm = 7.500 - 32/769(1940 - 2377°K) [Formula: see text] Osmium: Log Patm = 7.484 - 39/880(2157 - 2592°K) [Formula: see text] The indicated uncertainties are estimates of the overall limits of error.