The Atomic Weights of Zirconium and Hafnium

Abstract

IT is just a hundred years ago that the atomic weight of zirconium was determined by Berzelius. The method used, namely the analysis of the sulphate, yielded too low a value for the atomic weight, the same being the case in all the different methods used by his followers. This error was compensated, however, in part by the presence of 0.5 to 2 per cent. of a heavy element (hafnium) in their preparations (see NATURE, March 15, 1924). It was only in 1917 that Venable and Bell, when analysing ZrCl₄, used a more trustworthy method originating from T. W. Richards's laboratory. The values found by these investigators were appreciably higher than those found by their predecessors, and showed at the same time fluctuations for the values of the atomic weight, greater than should be expected considering the extreme precautions taken and the reliability of the method used.