Acronym, and
nickname, for Inhibited Red Fuming Nitric
Acid, the storable
oxidizer of choice for modern
liquid-fuel rockets (
hydrogen performs better, but it requires
cryogenic storage). Red fuming nitric acid is formed by passing
gaseous N
2O
4 through
garden variety nitric acid, HNO
3. To make the red fuming nitric acid more stable, it is inhibited by an addition of 0.6 percent hydrofluoric acid, HF. IRFNA reacts violently with
organic materials, releasing large amounts of heat, and usually starting fires.
Some common fuels used with IRFNA include
kerosenes,
hydrazines, and in much older rockets,
ethanols. IRFNA is highly
corrosive, and (surprise!)
toxic if ingested. Because it's so reactive, it is also possible to die from skin contact with IRFNA.
IRFNA, in addition to being an oxidizer for rocketry, can be combined with glycerin to make
nitroglycerin. Basic instructions can be found in the novel "
Fight Club", but for specifics, consult a chemistry manual.