Empirical Relations Between the Critical Constants of Fluid Alkali Metals

Abstract

It is demonstrated that Tc Kn c = constant for the critical constants of the alkali metals, where the exponent n is about 0.3. This is in marked contrast to the noble gases, where n is about—2. Further, the compressibility ratio pcVc/RTc for the alkalis ranges from 0.06 for Li to 0.20 for Cs, while for the noble gases the value is 0.29 ± 0.01. The importance of Coulomb forces in interpreting the results for the alkali metals is stressed.