Hydroxylammonium nitrate
Encyclopedia
Hydroxylammonium nitrate or hydroxylamine nitrate (HAN) is an energetic chemical with the chemical formula NH3OHNO3. It is the salt of hydroxylamine
Hydroxylamine
Hydroxylamine is an inorganic compound with the formula NH2OH. The pure material is a white, unstable crystalline, hygroscopic compound. However, hydroxylamine is almost always provided and used as an aqueous solution. It is used to prepare oximes, an important functional group. It is also an...

 and nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

. It is related to ammonium nitrate, but has a higher oxygen content. In its pure form, it is a hygroscopic solid.

Hydroxylammonium nitrate is unstable because of the reducing hydroxylammonium cation and the oxidizing nitrate anion.

It is usually used in aqueous solution. The solution is corrosive and toxic, and may be carcinogenic.

HAN is potentially unstable in presence of a strong oxidizer, such as nitric acid. Presence of trace amounts of metallic salts decreases markedly the stability of HAN solutions, and accidents have been reported (see references below).

HAN is being developed as a potential rocket propellant
Propellant
A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...

, both in the solid form as a solid propellant oxidizer, and in the aqueous solution in monopropellant
Monopropellant
Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety. While stable under defined storage conditions, they react very rapidly under certain other conditions to produce a large volume of energetic gases...

 rockets, including the Network Centric Airborne Defense Element
Network Centric Airborne Defense Element
The Network Centric Airborne Defense Element is an anti-ballistic missile system being developed by Raytheon for the Missile Defense Agency. On Sept. 18, 2008 Raytheon announced it had been awarded a $10 million contract to continue NCADE research and development...

 boost-phase interceptor being developed by Raytheon. It is typically bonded with glycidyl azide polymer (GAP), Hydroxyl-terminated polybutadiene
Hydroxyl-terminated polybutadiene
Hydroxyl-terminated polybutadiene is a polymer of butadiene terminated at each end with a hydroxyl functional group. It reacts with diisocyanate to form polyurethane, a stable and easily stored synthetic material....

 (HTPB), or carboxy-terminated polybutadiene (CTPB) and requires preheating to 200-300 °C to decompose. The catalyst is a noble metal, similar to the other monopropellant
Monopropellant
Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety. While stable under defined storage conditions, they react very rapidly under certain other conditions to produce a large volume of energetic gases...

s that use silver or palladium.

HAN is sometimes used in nuclear reprocessing
Nuclear reprocessing
Nuclear reprocessing technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel. Reprocessing serves multiple purposes, whose relative importance has changed over time. Originally reprocessing was used solely to extract plutonium for producing...

as a plutonium reductant.
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