On the vapour pressure of radon

Abstract

The few, rather scarce, and old data on the vapour pressure and sublimation pressure of radon are re-examined in light of the Wagner equation, which is applied for the first time (as far as we are aware) to the sublimation curve. Numerical coefficients have been established for the representation of both equilibrium curves, and estimates are advanced for the coordinates of the critical point, the triple-point, and the normal boiling temperature of radon. Some important thermodynamic properties, e.g., the enthalpies of vaporisation, sublimation, and fusion are derived, and a (p, T) phase diagram is sketched.

The fusion curves of xenon, krypton, and argon

“…While the bibliography on helium is extensive, including a significant number of specific monographs, the published data on the phase equilibrium of radon, which we examined recently [1], is much scarcer and old. For the other elements in the same group viz.…”

The sublimation of argon, krypton, and xenon

“…In the absence of measured values of these properties, one can try and describe the equilibrium curves through empirical equations. Using this latter procedure, we recently reported on the vapour pressure of radon [2] and on the fusion curves of Xe, Kr, and Ar [3]. In the years of 1960s, Ziegler and co-workers [4][5][6] analysed the experimental sublimation data for argon, krypton, and xenon, and devised a method to conjugate the information available to describe the (solid + vapour) equilibria.…”

Novel correlations between the critical constants of the noble gases

“…In the case of Rn, the values listed for P c and T c are from the recent re-evaluation by Ferreira and Lobo [14] of the early data (and still apparently the only precise ones) that were obtained by Gray and Ramsay [15]. From its format, the value for V c of 140.00 cm 3 mol −1 listed by Poling et al [13] is evidently an estimate; the value given in Table 1 is an extrapolation from the present Case C linear correlation for the quartet Ne-Xe (Section 2.4).…”

“…c Rn: the values of Pc and Tc are from the re-evaluation by Ferreira and Lobo [14] of the original data of Gray and Ramsay [15]. The value of Vc has then been estimated from Eq.…”