PETN (Pentaerythritol Tetranitrate) is one of the strongest known high explosives. It is more sensitive to shock or friction than TNT or tetryl, and it is never used alone as a booster. It is primarily used in booster and bursting charges of small caliber ammunition, in upper charges of detonators in some land mines and shells, and as the explosive core of primacord[?].

PETN is also used as a vasodilator.

PETN formula is C(CH₂ONO₂)₄. It melts toward 141°C. Its preparation involves nitration of pentaerythritol with a mixture of concentrated nitric and sulfuric acid.
C(CH₂OH)₄ + 4HNO₃ -> C(CH₂ONO₂)₄ + 4H₂O