Chemistry:Urea nitrate

Urea nitrate

Identifiers
CAS Number	124-47-0 Y
3D model (JSmol)	Interactive image
ChemSpider	29035 N
PubChem CID	31295
UNII	DHJ35702MG Y
InChI InChI=1S/CH4N2O.HNO3/c2*2-1(3)4/h(H4,2,3,4);(H,2,3,4) N Key: AYTGUZPQPXGYFS-UHFFFAOYSA-N N InChI=1/CH4N2O.HNO3/c2*2-1(3)4/h(H4,2,3,4);(H,2,3,4) Key: AYTGUZPQPXGYFS-UHFFFAOYAL
SMILES C(=O)(N)N.[N+](=O)(O)[O-]
Properties
Chemical formula	CH5N3O4
Molar mass	123.068 g/mol
Density	1.67±0.011 g/cm3
Melting point	157–159 °C (315–318 °F; 430–432 K)
Solubility in water	167.2±0.5 mg/mL
Solubility	Ethanol 14.2±0.1 mg/mL Methanol 54.8±0.9 mg/mL Acetone 10.4±0.2 mg/mL
Explosive data
Shock sensitivity	Low
Friction sensitivity	Low
Detonation velocity	4700 m/s
Hazards
GHS pictograms
GHS Signal word	DANGER
GHS hazard statements	H201, H271, H301, H304, H314, H332
GHS precautionary statements	P220, P233, P260, P250, P305+351+338
NFPA 704 (fire diamond)	1 2 3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Tracking categories (test):

• SizeSet

Crystals of urea nitrate

Urea nitrate is a fertilizer-based high explosive that has been used in improvised explosive devices in Afghanistan, Pakistan , Iraq, and various terrorist acts elsewhere in the world such as in the 1993 World Trade Center bombings. It has a destructive power similar to better-known ammonium nitrate explosives, with a velocity of detonation between 3,400 m/s (11,155 ft/s) and 4,700 m/s (15,420 ft/s). It has chemical formula of CH5N3O4 or (NH2)2COHNO3.

Urea nitrate is produced in one step by reaction of urea with nitric acid. This is an exothermic reaction, so steps must be taken to control the temperature.

Urea nitrate explosions may be initiated using a blasting cap.

Chemistry

Urea contains a carbonyl group. The more electronegative oxygen atom pulls electrons away from the carbon atom, forming a polar bond with greater electron density around the oxygen atom, giving it a partial negative charge. In a simplistic sense, nitric acid dissociates in aqueous solution into protons (hydrogen cations) and nitrate anions. The electrophilic proton contributed by the acid is attracted to the negatively charged oxygen atom on the urea molecule and the two form a covalent bond. The formed O-H bond is stabilized into a hydroxyl group when the oxygen abstracts an electron pair away from the central carbon atom, which leads to bond resonance between it and the two amino groups. As such, the urea cation can be thought of as a amidinium species. Paired with the spectator nitrate counteranion, it forms urea nitrate.

(NH₂)₂CO (aq) + HNO₃ (aq) → [(NH₂)₂COH]⁺[NO₃]⁻ (s)

The compound is favored by many amateur explosive enthusiasts as a principal explosive for use in larger charges. In this role it acts as a substitute for ammonium nitrate based explosives. This is due to the ease of acquiring the materials necessary to synthesize it, and its greater sensitivity to initiation compared to ammonium nitrate based explosives.

Further reading

• "Recovery and detection of urea nitrate in traces". J. Forensic Sci. 52 (6): 1284–90. November 2007. doi:10.1111/j.1556-4029.2007.00551.x. PMID 17868267. 
• Mr.X (July 2008). "Improvised Urea Nitrate". Aware EZine Gamma. http://www.awarenetwork.org/etc/gamma/?x=5. Retrieved 2008-11-11.