Hydroxylammonium nitrate

Hydroxylammonium nitrate

Identifiers
CAS Registry Number	13465-08-2 Y
ChemSpider	24259 Y
EC number	236-691-2
InChI InChI=1S/NO3.H4NO/c2-1(3)4;1-2/h;2H,1H3/q-1;+1 Y Key: CRJZNQFRBUFHTE-UHFFFAOYSA-N Y InChI=1/NO3.H4NO/c2-1(3)4;1-2/h;2H,1H3/q-1;+1 Key: CRJZNQFRBUFHTE-UHFFFAOYAP
Jmol-3D images	Image
PubChem	26045
SMILES [NH3+]O.[N+](=O)([O-])[O-]
Properties
Chemical formula	H4N2O4
Molar mass	96.04 g/mol
Solubility in water	Soluble
Hazards
MSDS	External MSDS (as 18 % solution)
EU Index	007-028-00-2
EU classification	Explosive (E) Carc. Cat. 3 Toxic (T) Harmful (Xn) Irritant (Xi) Dangerous for the environment (N)
R-phrases	R2, R22, R24, R36/38, R40, R43, R48/22, R50
S-phrases	(S1/2), S26, S36/37, S45, S61
Related compounds
Other anions	Hydroxylammonium sulfate Hydroxylammonium chloride
Other cations	Ammonium nitrate
Related compounds	Hydroxylamine
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Hydroxylammonium nitrate or hydroxylamine nitrate (HAN) is an inorganic compound with the chemical formula NH₃OHNO₃. It is a salt derived from hydroxylamine and nitric acid. In its pure form, it is a colourless hygroscopic solid. It has potential to be used as a rocket propellant either as a solution in monopropellants or bipropellants.^[1]

Properties

The compound is a salt with separated hydroxyammonium and nitrate ions.^[2] Hydroxylammonium nitrate is unstable because it contains both a reducing agent (hydroxylammonium cation) and an oxidizer (nitrate),^[3] the situation being analogous to ammonium nitrate. It is usually handled as an aqueous solution. The solution is corrosive and toxic, and may be carcinogenic. Solid HAN is unstable, particularly in the presence of trace amounts of metal salts.

Applications

HAN is a potential rocket propellant, both in the solid form as a solid propellant oxidizer, and in the aqueous solution in monopropellant rockets, including the Network Centric Airborne Defense Element boost-phase interceptor being developed by Raytheon.^[4] It is typically bonded with glycidyl azide polymer (GAP), hydroxyl-terminated polybutadiene (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 monopropellants that use silver or palladium.

It will be used as monopropellant in the high thrust engines of the Green Propellant Infusion Mission in 2016 aboard a Falcon Heavy.^[5][6][7] Catalysts are: platinum, iridium and rhodium. Its specific impulse is about 220-250 s. It has higher performance than hydrazine,^[5][7] is more dense (less volume per mass) and has a freezing point at 243 K (−30 °C; −22 °F).

HAN is sometimes used in nuclear reprocessing as a reducing agent for plutonium ions.

Bibliography

• Donald G. Harlow et al. (1998). "Technical Report on Hydroxlyamine Nitrate". U.S. Department of Energy. DOE/EH-0555
• Gösta Bengtsson et al. (2002) "The kinetics and mechanism of oxidation of hydroxylamine by iron(III)". J. Chem. Soc., Dalton Trans., 2002, 2548–2552

References