chlorine trifluoride

Chlorine trifluoride, ClF₃, or "CTF" as the engineers insist on calling it, is a colorless gas, a greenish liquid, or a white solid. It boils at 12° (so that a trivial pressure will keep it liquid at room temperature) and freezes at a convenient —76°... It is also quite probably the most vigorous fluorinating agent in existence—much more vigorous than fluorine itself... It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water—with which it reacts explosively.

1972, John Drury Clark, Ignition!, page 73