What Is the Most Flammable Chemical?

Comparing Chemical Flammability

Toxic Substance
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Have you ever wondered what material burns the best? Here's a look at the most flammable chemical.

Although hydrogen is the most flammable element, the most flammable chemical probably is chlorine trifluoride, ClF3. This is a colorless, toxic, corrosive gas or pale greenish-yellow liquid that is so reactive that it initiates combustion of just about any material you can name, and it doesn't even require an ignition source to get the fire started! The reactions are vigorous and often violent to the point of explosivity.

Burning the Unburnable

Chlorine trifluoride's fluorination and oxidation power surpasses the oxidizing power of oxygen, which allows the chemical to ignite materials normally considered fire-safe, such as oxides. Chlorine trifluoride burns asbestos, sand, glass, concrete, and even flame retardants. Most fire control and suppression systems are ineffective or else actually worsen the resulting fire. The chemical also ignites human skin and other tissue on contact, producing hydrochloric acid and hydrofluoric acid. Both acids burn human tissue. Hydrofluoric acid selectively activates pain centers and attacks bone, causing potentially lethal poisoning.

Uses of Chlorine Trifluoride

The properties that make chlorine trifluoride so flammable also make it useful. The chemical has applications in nuclear reactor fuel processing, semiconductor production, and industrial operations. It is a component of rocket fuel, a powerful industrial cleaner, and an etchant. Its primary use is producing uranium hexafluoride, UF6, for nuclear fuel processing and reprocessing:

U + 3 ClF3 → UF6 + 3 ClF