Taming the Beast
Total Page:16
File Type:pdf, Size:1020Kb
Inorganic Stamp Corner by Daniel Rabinovich Taming the Beast The French chemist Henri Moissan (1852-1907) was awarded the 1906 Nobel Prize in Chemistry for two rather different areas of scientific endeavor, namely the isolation of elemental fluorine and the introduction of the electric furnace in the preparation of metal carbides and other refractory materials. The selection committee of the Royal Swedish Academy of Sciences had a particularly difficult task that year, and Moissan edged out by a single vote (5-4) no one less than Dmitri Mendeleev, of periodic table fame. Unfortunately the renowned Russian chemist, who was considered an eccentric genius but an outsider in the European establishment, never got a chance to be nominated again since he died of influenza on February 2, 1907. As bad luck would have it, Moissan himself died from acute appendicitis only 18 days later, shortly after returning to Paris from his trip to Stockholm. The isolation of fluorine in 1886 was a remarkable achievement given the extreme reactivity of this element. Moissan succeeded by electrolyzing at -25 °C a solution of potassium hydrogen fluoride (KHF2) dissolved in anhydrous hydrogen fluoride, using special platinum– iridium electrodes in a platinum U-shaped vessel capped with fluorite (CaF2) stoppers. Not exactly an experiment undergraduate students conduct today in a laboratory course! In any event, Moissan’s electrolytic cell is depicted on the two French stamps shown herein. Interestingly, the stamp on the left, released in 1986 to commemorate fluorine’s centennial, displays the incorrect (reverse) chemical equation, i.e., hydrogen does react with fluorine to yield hydrogen fluoride, but that is evidently not how the lightest halogen was isolated in the first place! .