The story of an especially extreme chemical compound that was deemed too dangerous for usage in weapons even by the Nazis.

In 1939, weapons technicians working in Nazi labs on the German-Polish border discovered an incredible new material that they code named "Substance N." This mysterious chemical compound displayed an array of exceptional properties - it boiled when exposed to air, it exploded when it came into contact with water, it proved lethal if inhaled, and when allowed to decompose, it produced large quantities of deadly hydrofluoric acid. If loaded into a flamethrower and ignited, "Substance N" burned at temperatures exceeding 2,400°C. Upon discovery, a plan was formulated to arm front line troops with "Substance N" but after further testing and research, it was deemed far too dangerous and volatile to be used.

The obvious question is, what was it? What chemical nightmare had the Nazis stumbled across? Later scientific study was able to isolate "Substance N" as a chemical called chlorine trifluoride, or ClF3. This compound is the single most effective fluorinating agent known to mankind. ClF3 is considerably more dangerous to handle than even fluorine gas is, which is an incredibly rare feat. It is also a much better oxidizer than even oxygen.

In fact, chlorine trifluoride is such a powerful oxidizer that it can even burn things that are traditionally thought of as being inflammable, including bricks, asbestos, and substances which have already been lit on fire and burned.

For an extremely short period of time, American rocket scientists considered using ClF3 as fuel in spacecraft. The proposal was abandoned very quickly after the first round of testing concluded that this idea was what is known in scientific circles as...bad. It was a bad idea.

ClF3 is still produced today, and is used by companies that manufacture semiconductor components to clean their equipment.