Page:Text-book of Electrochemistry.djvu/77

 62 BOILING AND FREEZING POINT. chap.

molecular weights found for aluminium, antimony, and bis- muth are considerably greater than the atomic weights of these elements, indicating that their molecules consist of several, probably two, atoms. On the whole, the results agree remarkably well with what is known of the molecular weights of the metals in the gaseous state.

Eamsay*s observations have been confirmed by the ex- l)eriments on the freezing points of metal alloys made by Tammann. From his results, Tammann (12) calculated the molecular weights of some metals, and these, along with the corresponding atomic weights, are contained in the following table : —

��SOLITIONS (IT

MeUl.

�IN Merc DRV (theoretical) =

Mol. welgt

�(Tammann). = 425.

It. Atom, weight.

�Potassium Sodium. . Thallium Zinc.

��Heycock and Neville (IJ) made similai- experiments, using sodium, and afterwards tin, bismuth, cadmium, lead, thallium, and zinc, as solvent. In the next table some of. their results are reproduced; the numbers given are the depressions of the freezing point produced by the solution of a gram-atom of the metal in 1880 grams of tin. The theoretical value is 2*98.

Indium l-8(i

�� �