Technetium occurrence

Progress in understanding stellar evolution and nucleosynthesis, and the discovery by Merrill (1952) of the unstable element technetium in the S star R Andromedae, demonstrating the occurrence of stellar nucleosynthesis within a few half-lives of Tc (i.e. < about 1 Myr see Fig. 1.8), has led to acceptance of the idea that abundance variations among stars are perfectly natural as a consequence of three main effects (see Fig. 3.37) ... 

Occurrence. The natural abundance of Tc is negligibly small. Technetium is a by-product of the nuclear industry and it is a product of the uranium decay. 

Until technetium was produced by nuclear reactions there had been numerous efforts to demonstrate the occurrence of the lacking element in the nature. In this context, the works of Noddack and Tacke as well as Berg and Tacke should be... 

G.E. Boyd and W.V. Larson, Report on the occurrence of technetium on the earth s crust, Journal of Physical Chemistry 60 (1956) 707-715. Translation in K. U. Leuven Archives, Noddack-Tacke Papers, 1316. See also the lists of publications on rhenium and technetium, 1954 and 1956,... 

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