Hydroxylammonium nitrate

Hydroxylammonium Nitrate or hydroxylamine Nitrate (HAN) is an energetic chemical with the chemical formula NH3OHNO3. It is the salt of hydroxylamine and nitric acid. It is related to ammonium nitrate, but has a higher oxygen content. In its pure form, it is a hygroscopic solid.

It is usually used in aqueous solution. The solution is corrosive and toxic, but is not believed to be carcinogenic. HAN MSDS can be found on the web (example: Sachem MSDS for HAN 2 M).

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 researched as a potential rocket propellant, both in the solid form as a solid propellant oxidizer, and in the aqueous solution in monopropellant rockets. It is typically bonded with glycidyl azide polymer (GAP), Hydroxyl-terminated polybutadiene (HTPB), or Carboxy-Terminated Polybutadiene (CTPB) and requires preheating to 200-300 deg C to decompose. The catalyst is a noble metal, similar to the other monopropellants that use silver or palladium.

HAN is sometimes used in nuclear reprocessing as a plutonium reductant.