Title: Vapor pressure and heat of sublimation of tungsten
Abstract: The vapor pressure of tungsten was measured by the Langmuir method in the temperature range 2574 to 3183 °K using a vaccum microbalance. The least-squares line through the data, logP(atm) = 7.790-44680/T, yields a second law ΔHs° (2850 °K) = 204.4 ±2.7 kcal/mol and ΔSs° (2850 °K) = 35.64 ±0.97 cal/mol deg. Our recommended equation for the vapor pressure is logP(atm) = 7.933 - 45087/T based on our experimentally determined mean third law ΔHs° (298 °K) =203.5 kcal/mol and tabulated values for the entropies and enthalpies.