Urea nitrate is a fertilizer-based
high explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...
that has been used in
improvised explosive device
An improvised explosive device (IED) is a bomb constructed and deployed in ways other than in conventional warfare, conventional military action. It may be constructed of conventional military explosives, such as an artillery shell, attached t ...
s in
Afghanistan
Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central Asia and South Asia. It is bordered by Pakistan to the Durand Line, east and south, Iran to the Afghanistan–Iran borde ...
,
Pakistan
Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
,
Iraq
Iraq, officially the Republic of Iraq, is a country in West Asia. It is bordered by Saudi Arabia to Iraq–Saudi Arabia border, the south, Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq border, the east, the Persian Gulf and ...
, and various
terrorist
Terrorism, in its broadest sense, is the use of violence against non-combatants to achieve political or ideological aims. The term is used in this regard primarily to refer to intentional violence during peacetime or in the context of war aga ...
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
Ammonium nitrate is a chemical compound with the formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, but does not form hydrates. It is predominantly us ...
explosives, with a
velocity of detonation
Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonation, detonated explosive. Explosive velocities are always higher than the local speed of s ...
between and .
It has chemical formula of or .
Urea nitrate is produced in one step by reaction of
urea
Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...
with
nitric acid
Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...
. This is an
exothermic reaction
In thermochemistry, an exothermic reaction is a "reaction for which the overall standard enthalpy change Δ''H''⚬ is negative." Exothermic reactions usually release heat. The term is often confused with exergonic reaction, which IUPAC define ...
, so steps must be taken to control the temperature.
It was discovered in 1797 by
William Cruickshank,
inventor of the
Chloralkali process
The chloralkali process (also chlor-alkali and chlor alkali) is an industrial process for the electrolysis of sodium chloride (NaCl) solutions. It is the technology used to produce chlorine and sodium hydroxide (caustic soda), which are commodi ...
.
Urea nitrate explosions may be initiated using a
blasting cap
A detonator is a device used to make an explosive or explosive device explode. Detonators come in a variety of types, depending on how they are initiated (chemically, mechanically, or electrically) and details of their inner working, which of ...
.
Chemistry
Urea contains a
carbonyl group
In organic chemistry, a carbonyl group is a functional group with the formula , composed of a carbon atom double-bonded to an oxygen atom, and it is divalent at the C atom. It is common to several classes of organic compounds (such as aldehydes ...
. 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.
:
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.
References
Further reading
*
*
External links
*{{Commonscatinline
Explosive chemicals
Nitrates
Ureas