Where Should Elements 43 and 75 Be Looked For

River gravel, for example from the Ural Mountains, was at this time an important initial material for platinum extraction. Before weathering the rock is composed of olivine stones in which veins of chromite are present In these chromite veins platinum metals are present as grains and spots. In the weathered product platinum metals (groups 8-10) are found along with Cu, Ag and Au from group 11. 

Columbite contains niobium and tantalum as oxides in minerals that form a continuous series between the two end minerals niohite (Fe,Mn)(Nb,Ta)20. and tantalite (Fe,Mn)(Ta,Nb)20g. 

These minerals are accompanied by other very complex minerals containing yttrium, cerium, erbium, uranium, thorium, titanium, zirconium and tungsten, i.e. elements in groups 3, 4, 5 and 6. 

With the final result available it is easy to be wise and note that when the two scientists made their analysis and found group 6 of interest they specifically mentioned 

Walter Noddack and Ida Tacke (Mn and Mrs. Noddack) started systematic experimental attempts to find elements 43 and 75 in 1922. They worked partly at the physical-chemical institution at the University of Berlin, partly at the Physico-Technical Testing Institute (Physikahsch-Technische Reichsanstalt). Otto Berg at Siemens Halske took part in the work as an expert on spectroscopic investigations. 

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