Superconductivity and the Debye Characteristic Temperature

A plot of the superconducting threshold temperatures as a function of the Debye characteristic temperatures of the known superconducting elements discloses a number of interesting relationships. These relationships, in conjunction with previously known empirical rules, are used to discuss the occurrence of superconduction among other elements. It is concluded that Sc, Y, and Sm are not likely to be found superconducting, but that Ce, Pr, Nd, and Ac (should its atomic volume prove to be of the order of 22 cm³/mole) are expected to be superconducting. Data on Pa is very sketchy. The best that can be inferred is that Pa should be superconducting with a threshold temperature in excess of 2^∘{}K.