The group 7 elements, unlike the members of certain other groups, have widely divergent histories. The manganese mineral, pyrolusite, for example, has been used for thousands of years in the making of glass, while the other group members were only discovered in the twentieth century. Technetium was the first new element to be synthesized by scientists, and rhenium was the last of the elements to be found in nature.
Manganese was recognized as an element by the Swedish chemist, Carl Wilhelm Scheele, in 1774, and isolated the same year by his compatriot, Johan Gottlieb Gahn. It was discovered in pyrolusite, and also occurs in the mineral, psilomelane.
Rhenium was discovered in 1925 by the German chemists, Walter Noddack, Ida Noddack, and Otto Berg, in the mineral, gadolinite. It can also be found in molybdenite and wolframite. The same team also claimed, incorrectly, to have discovered technetium, which was in fact discovered in 1937, when synthesized by Emilio SegrĪ and Carlo Perrier in the particle accelerator at the University of Berkeley, California.
