Equilibrium volumes of body-centered cubic alkali metals related to critical constants

Regularities at the first-order body-centered cubic to face-centered cubic transition induced by pressure are first shown to relate to the critical thermodynamic constants of the five alkali metals from Li to Cs. The melting transition at atmospheric pressure is then correlated with the critical temperatures. Finally, though we recognize that Fr (Z=87) has a half-life of only 22 min, predictions are made of its critical constants assuming it to be a body-centered cubic alkali metal.