The cadmium molecule, as shown by determinations of the density of its vapour, is monatomic. The metal unites with the majority of the heavy metals to form alloys; some of these, the so-called fusible alloys, find a useful application from the fact that they possess a low melting-point.
In the more complex gases the specific heat varies considerably with temperature; only in the case of monatomic gases does it remain constant.
If two monatomic molecules, having energy of translation only, equivalent to 3 degrees of freedom, combined to form a diatomic molecule with 5 degrees of freedom, the energy lost would.
The same value had previously been found for mercury vapour by Kundt and Warburg, and had been regarded as confirmatory of the monatomic character attributed on chemical grounds to the mercury molecule.
This Appears To Be Actually The Case For Monatomic Gases Such As Mercury Vapour (Kundt And Warburg, 1876), Argon And Helium (Ramsay, 1896).