Gaseous Diffusion: The Systems He–Kr, Ar–Kr, and Kr–Xe

Gaseous diffusion coefficients are reported for the systems He–Kr, Ar–Kr, and Kr–Xe. The results were obtained over the temperature range 0° to 120°C with an apparatus of the Ney—Armistead type and can be described by the following expressions: He–Kr, log10D12=1.688 log10T−4.3844; Ar–Kr, log10D12=1.917 log10T−5.6017; Kr–Xe, log10D12=1.858 log10T−5.7108, wherein the diffusion coefficients have been reduced to 1 atm pressure and refer to diffusion involving only trace quantities of the heavier component. The experimental data compare favorably with results derived from viscosity measurements, but show deviations for thermal-conductivity-derived values, which appear to become progressively larger as the mass difference of the gas pair increases.