Critical Properties of n-Alkanes and the Relevance of Polymer Models to the Heavy Fluid Metals Rb and Cs

Abstract

n-alkane critical constants as determined experimentally for n ≤ 18 are first compared and contrasted with the predictions of various models. Qualitative accord is found, but only one quantitative prediction, that of Wertheim's model for the critical temperature T_c, is found to fit the experimental data over the admittedly limited range of n available.

Reference is then made to critical properties of the heavy fluid alkali metals, and especially Rb and Cs, where some evidence is cited for the existence of long chains of alkali atoms. The relative constancy of the product of the critical pressure P_c and the critical volume V_c for the three heaviest alkalis is noted, a fact consistent with one of the more recent ‘polymer’ models.