The French chemist Henri Moissan (1852--1907) won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds.
Fluorine's existence had been well known for many years, but all attempts to prepare it had failed - and some experimenters had died in the attempt.
When prepared, it immediately attacked anything around it and vanished again. Even gold was not impervious to the attacks of elemental fluorine. Moissan eventually succeded by electrolysing a solution of potassium hydrogen fluoride (KHF) and hydrogen fluoride (HF). The mixture was needed because HF is a non-conductor. The device was built with platinum/iridium electrodes in a platinum holder and cooled the apparatus to -50 °Celsius. The result was to completely isolate the hydrogen produced from the negative electrode from the fluorine produced at the positive one. This is essentially still the way fluorine is produced today.
Moissan went on to study fluorine chemistry in great detail, contributed to the development of the electric arc furnace and attempted to use pressure to synthesise diamonds from the more common form of carbon.
He died suddenly in Paris in February 1907, shortly after his return from receiving the Nobel Prize in Stockholm. It is not known whether his experiments with fluorine contributed to his early death.