180 °C, 453 K, 356 °F (decomposes above 150 °C)

Pentaerythritol tetranitrate (PETN, also known as PENT, PENTA, TEN, corpent, penthrite, or rarely and primarily in German as nitropenta) is one of the most powerful high explosives known, with a relative effectiveness factor (R.E. factor) of 1.66. In addition to being used as a plastic explosive, it is also used as a vasodilator drug to treat certain heart conditions.

The most common use of PETN is as an explosive with high brisance. It is more difficult to detonate than primary explosives, so dropping or igniting it will typically not cause an explosion (at atmospheric pressure it is difficult to ignite and burns relatively slowly), but is more sensitive to shock and friction than other high explosives such as TNT or tetryl. Under certain conditions deflagration to detonation transition can occur.

It is rarely used alone, but 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 detonation cord. PETN is the least stable of the common military explosives, but can be stored without significant deterioration for longer than nitroglycerin or nitrocellulose. It is also used in exploding bridgewire detonators, either alone or with a subsequent booster charge. In spark detonators, PETN is used to avoid need for primary explosives; the energy needed for a successful direct initiation of PETN by an electric spark ranges between 10-60 mJ.

Its basic explosion characteristics are:

PETN is used in a number of compositions. It is a major ingredient of the Semtex plastic explosive. It is also used as a component of pentolite, a 50/50 blend with TNT; a shaped charge of 8 oz of pentolite, used in the M9A1 (bazooka) rockets, can penetrate up to 5 inches of armor. The XTX8003 extrudable explosive, used in the W68 and W76 nuclear warheads, is a mixture of 80% PETN and 20% of Sylgard 182, a silicone rubber. It is often phlegmatized by addition of 5-40% of wax, or by polymers (producing polymer-bonded explosives); in this form it is used in some cannon shells up to 30mm caliber, though unsuitable for higher calibers. It is also used as a component of some gun propellants and solid rocket propellants. Nonphlegmatized PETN is stored and handled with approximately 10% water content.

PETN alone can not be cast as it explosively decomposes slightly above its melting point, but it can be mixed with other explosives to form castable mixtures.

PETN can be initiated by a laser. A pulse with duration of 25 nanoseconds and 0.5-4.2 joules of energy from a Q-switched ruby laser can initiate detonation of a PETN surface coated with a 100 nm thick aluminium layer in less than half microsecond.

Neutron radiation degrades PETN, producing carbon dioxide and some pentaerythritol dinitrate and trinitrate. Gamma radiation increases the thermal decomposition sensitivity of PETN, lowers melting point by few degrees C and causes swelling of the samples.

Like other nitrate esters, the primary degradation mechanism is the loss of nitrogen dioxide; this reaction is autocatalytic. The subsequent step is loss of formaldehyde. Studies were performed on thermal decomposition of PETN.