Explosive material

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File:17. Експлозивни својства на три различни типови експлозиви.webm

Demonstration of the explosive properties of three different explosives. Each explosive is set on a solid marble base and is initiated by a glowing wooden stick.

An explosive material, also called an explosive, 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 lightheatsound, and pressure. An explosive charge is a measured quantity of explosive material, which may be composed of a single ingredient or a combination of two or more.

The potential energy stored in an explosive material may, for example, be

Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be “high explosives” and materials that deflagrate are said to be “low explosives”. Explosives may also be categorized by their sensitivity. Sensitive materials that can be initiated by a relatively small amount of heat or pressure are primary explosives and materials that are relatively insensitive are secondary or tertiary explosives.

A wide variety of chemicals can explode; a smaller number are manufactured specifically for the purpose of being used as explosives. The remainder are too dangerous, sensitive, toxic, expensive, unstable, or prone to decomposition or degradation over short time spans.

In contrast, some materials are merely combustible or flammable if they burn without exploding.

The distinction, however, is not razor-sharp. Certain materials—dusts, powders, gasses, or volatile organic liquids—may be simply combustible or flammable under ordinary conditions, but become explosive in specific situations or forms, such as dispersed airborne clouds, or confinement or sudden release.


At its root, the history of chemical explosives lies in the history of gunpowder.[1][2] During the Tang Dynasty in the 9th century, Taoist Chinese alchemists were eagerly trying to find the elixir of immortality.[3] In the process, they stumbled upon the explosive invention of gunpowder made from coal, saltpeter, and sulfur in 1044. Gunpowder was the first form of chemical explosives and by 1161, the Chinese were using explosives for the first time in warfare.[4][5][6] The Chinese would incorporate explosives fired from bamboo or bronze tubes known as bamboo fire crackers. The Chinese also used inserted rats from inside the bamboo fire crackers to fire toward the enemy, creating great psychological ramifications – scaring enemy soldiers away and causing cavalry units to go wild.[7]

Though early thermal weapons, such as Greek fire, have existed since ancient times, the first widely used explosive in warfare and mining was black powder, invented in 9th century in China by Song Chinese alchemists. This material was sensitive to water, and it produced copious amounts of dark smoke. The first useful explosive stronger than black powder was nitroglycerin, developed in 1847. Since nitroglycerin is a liquid and highly unstable, it was replaced by nitrocelluloseTNT in 1863, smokeless powderdynamite in 1867 and gelignite (the latter two being sophisticated stabilized preparations of nitroglycerin rather than chemical alternatives, both invented by Alfred Nobel). World War I saw the adoption of TNT trinitrotoluene in artillery shells. World War II saw an extensive use of new explosives (see explosives used during World War II). In turn, these have largely been replaced by more powerful explosives such as C-4 and PETN. However, C-4 and PETN react with metal and catch fire easily, yet unlike TNT, C-4 and PETN are waterproof and malleable.[8]


File:Blast Area Security.webm

A video on safety precautions at blast sites


File:Handling Explosives in Underground Mines.webm

A video describing how to safely handle explosives in mines.

The largest commercial application of explosives is mining. Whether the mine is on the surface or is buried underground, the detonation or deflagration of either a high or low explosive in a confined space can be used to liberate a fairly specific sub-volume of a brittle material in a much larger volume of the same or similar material. The mining industry tends to use nitrate-based explosives such as emulsions of fuel oil and ammonium nitrate solutions, mixtures of ammonium nitrate prills (fertilizer pellets) and fuel oil (ANFO) and gelatinous suspensions or slurries of ammonium nitrate and combustible fuels.

In Materials Science and Engineering, explosives are used in cladding. A thin plate of some material is placed atop a thick layer of a different material, both layers typically of metal. Atop the thin layer is placed an explosive. At one end of the layer of explosive, the explosion is initiated. The two metallic layers are forced together at high speed and with great force. The explosion spreads from the initiation site throughout the explosive. Ideally, this produces a metallurgical bond between the two layers.

As the length of time the shock wave spends at any point is small, we can see mixing of the two metals and their surface chemistries, through some fraction of the depth, and they tend to be mixed in some way. It is possible that some fraction of the surface material from either layer eventually gets ejected when the end of material is reached. Hence, the mass of the now “welded” bilayer, may be less than the sum of the masses of the two initial layers.

There are applications where a shock wave, and electrostatics, can result in high velocity projectiles.






The international pictogram for explosive substances.

An explosion is a type of spontaneous chemical reaction that, once initiated, is driven by both a large exothermic change (great release of heat) and a large positive entropy change (great quantities of gases are released) in going from reactants to products, thereby constituting a thermodynamically favorable process in addition to one that propagates very rapidly. Thus, explosives are substances that contain a large amount of energy stored in chemical bonds. The energetic stability of the gaseous products and hence their generation comes from the formation of strongly bonded species like carbon monoxide, carbon dioxide, and (di)nitrogen, which contain strong double and triple bonds having bond strengths of nearly 1 MJ/mole. Consequently, most commercial explosives are organic compounds containing -NO2-ONO2 and -NHNO2 groups that, when detonated, release gases like the aforementioned (e.g., nitroglycerinTNTHMXPETNnitrocellulose).[9]

An explosive is classified as a low or high explosive according to its rate of burn: low explosives burn rapidly (or deflagrate), while high explosives detonate. While these definitions are distinct, the problem of precisely measuring rapid decomposition makes practical classification of explosives difficult.

Traditional explosives mechanics is based on the shock-sensitive rapid oxidation of carbon and hydrogen to carbon dioxide, carbon monoxide and water in the form of steam. Nitrates typically provide the required oxygen to burn the carbon and hydrogen fuel. High explosives tend to have the oxygen, carbon and hydrogen contained in one organic molecule, and less sensitive explosives like ANFO are combinations of fuel (carbon and hydrogen fuel oil) and ammonium nitrate. A sensitizer such as powdered aluminum may be added to an explosive to increase the energy of the detonation. Once detonated, the nitrogen portion of the explosive formulation emerges as nitrogen gas and toxic nitric oxides.


The chemical decomposition of an explosive may take years, days, hours, or a fraction of a second. The slower processes of decomposition take place in storage and are of interest only from a stability standpoint. Of more interest are the other two rapid forms besides decomposition: deflagration and detonation.


In deflagration, decomposition of the explosive material is propagated by a flame front which moves slowly through the explosive material at speeds less than the speed of sound within the substance (usually below 1000 m/s) [10] in contrast to detonation, which occurs at speeds greater than the speed of sound. Deflagration is a characteristic of low explosive material.


This term is used to describe an explosive phenomenon whereby the decomposition is propagated by an explosive shock wave traversing the explosive material at speeds greater than the speed of sound within the substance.[11] The shock front is capable of passing through the high explosive material at supersonic speeds, typically thousands of metres per second.


In addition to chemical explosives, there are a number of more exotic explosive materials, and exotic methods of causing explosions. Examples include nuclear explosives, and abruptly heating a substance to a plasma state with a high-intensity laser or electric arc.

Laser- and arc-heating are used in laser detonators, exploding-bridgewire detonators, and exploding foil initiators, where a shock wave and then detonation in conventional chemical explosive material is created by laser- or electric-arc heating. Laser and electric energy are not currently used in practice to generate most of the required energy, but only to initiate reactions.

Properties of explosive materials[edit]

To determine the suitability of an explosive substance for a particular use, its physical properties must first be known. The usefulness of an explosive can only be appreciated when the properties and the factors affecting them are fully understood. Some of the more important characteristics are listed below:


Sensitivity refers to the ease with which an explosive can be ignited or detonated, i.e., the amount and intensity of shockfriction, or heat that is required. When the term sensitivity is used, care must be taken to clarify what kind of sensitivity is under discussion. The relative sensitivity of a given explosive to impact may vary greatly from its sensitivity to friction or heat. Some of the test methods used to determine sensitivity relate to:

  • Impact — Sensitivity is expressed in terms of the distance through which a standard weight must be dropped onto the material to cause it to explode.
  • Friction — Sensitivity is expressed in terms of what occurs when a weighted pendulum scrapes across the material (it may snap, crackle, ignite, and/or explode).
  • Heat — Sensitivity is expressed in terms of the temperature at which flashing or explosion of the material occurs.

Specific explosives (usually but not always highly sensitive on one or more of the three above axes) may be idiosyncratically sensitive to such factors as pressure drop, acceleration, the presence of sharp edges or rough surfaces, incompatible materials, or even—in rare cases—nuclear or electromagnetic radiation. These factors present special hazards that may rule out any practical utility.

Sensitivity is an important consideration in selecting an explosive for a particular purpose. The explosive in an armor-piercing projectile must be relatively insensitive, or the shock of impact would cause it to detonate before it penetrated to the point desired. The explosive lenses around nuclear charges are also designed to be highly insensitive, to minimize the risk of accidental detonation.

Sensitivity to initiation[edit]

The index of the capacity of an explosive to be initiated into detonation in a sustained manner. It is defined by the power of the detonator which is certain to prime the explosive to a sustained and continuous detonation. Reference is made to the Sellier-Bellot scale that consists of a series of 10 detonators, from n. 1 to n. 10, each of which corresponds to an increasing charge weight. In practice, most of the explosives on the market today are sensitive to an n. 8 detonator, where the charge corresponds to 2 grams of mercury fulminate.

Velocity of detonation[edit]

The velocity with which the reaction process propagates in the mass of the explosive. Most commercial mining explosives have detonation velocities ranging from 1800 m/s to 8000 m/s. Today, velocity of detonation can be measured with accuracy. Together with density it is an important element influencing the yield of the energy transmitted for both atmospheric over-pressure and ground acceleration. By definition, a “low explosive,” such as black powder, or smokeless gunpowder has a burn rate of 171–631 m/s.[12] In contrast, a “high explosive,” whether a primary, such as detonating cord, or a secondary, such as TNT or C-4 has a significantly higher burn rate.[13]


Stability is the ability of an explosive to be stored without deterioration.

The following factors affect the stability of an explosive:

  • Chemical constitution. In the strictest technical sense, the word “stability” is a thermodynamic term referring to the energy of a substance relative to a reference state or to some other substance. However, in the context of explosives, stability commonly refers to ease of detonation, which is concerned with kinetics (i.e., rate of decomposition). It is perhaps best, then, to differentiate between the terms thermodynamically stable and kinetically stable by referring to the former as “inert.” Contrarily, a kinetically unstable substance is said to be “labile.” It is generally recognized that certain groups like nitro (–NO2), nitrate (–ONO2), and azide (–N3), are intrinsically labile. Kinetically, there exists a low activation barrier to the decomposition reaction. Consequently, these compounds exhibit high sensitivity to flame or mechanical shock. The chemical bonding in these compounds is characterized as predominantly covalent and thus they are not thermodynamically stabilized by a high ionic-lattice energy. Furthermore, they generally have positive enthalpies of formation and there is little mechanistic hindrance to internal molecular rearrangement to yield the more thermodynamically stable (more strongly bonded) decomposition products. For example, in lead azide, Pb(N3)2, the nitrogen atoms are already bonded to one another, so decomposition into Pb and N2[1] is relatively easy.
  • Temperature of storage. The rate of decomposition of explosives increases at higher temperatures. All standard military explosives may be considered to have a high degree of stability at temperatures from –10 to +35 °C, but each has a high temperature at which its rate of decomposition rapidly accelerates and stability is reduced. As a rule of thumb, most explosives become dangerously unstable at temperatures above 70 °C.
  • Exposure to sunlight. When exposed to the ultraviolet rays of sunlight, many explosive compounds containing nitrogen groups rapidly decompose, affecting their stability.
  • Electrical discharge. Electrostatic or spark sensitivity to initiation is common in a number of explosives. Static or other electrical discharge may be sufficient to cause a reaction, even detonation, under some circumstances. As a result, safe handling of explosives and pyrotechnics usually requires proper electrical grounding of the operator.

Power, performance, and strength[edit]

The term power or performance as applied to an explosive refers to its ability to do work. In practice it is defined as the explosive’s ability to accomplish what is intended in the way of energy delivery (i.e., fragment projection, air blast, high-velocity jet, underwater shock and bubble energy, etc.). Explosive power or performance is evaluated by a tailored series of tests to assess the material for its intended use. Of the tests listed below, cylinder expansion and air-blast tests are common to most testing programs, and the others support specific applications.

  • Cylinder expansion test. A standard amount of explosive is loaded into a long hollow cylinder, usually of copper, and detonated at one end. Data is collected concerning the rate of radial expansion of the cylinder and the maximum cylinder wall velocity. This also establishes the Gurney energy or 2E.
  • Cylinder fragmentation. A standard steel cylinder is loaded with explosive and detonated in a sawdust pit. The fragments are collected and the size distribution analyzed.
  • Detonation pressure (Chapman-Jouguet condition). Detonation pressure data derived from measurements of shock waves transmitted into water by the detonation of cylindrical explosive charges of a standard size.
  • Determination of critical diameter. This test establishes the minimum physical size a charge of a specific explosive must be to sustain its own detonation wave. The procedure involves the detonation of a series of charges of different diameters until difficulty in detonation wave propagation is observed.
  • Massive-diameter detonation velocity. Detonation velocity is dependent on loading density (c), charge diameter, and grain size. The hydrodynamic theory of detonation used in predicting explosive phenomena does not include the diameter of the charge, and therefore a detonation velocity, for a massive diameter. This procedure requires the firing of a series of charges of the same density and physical structure, but different diameters, and the extrapolation of the resulting detonation velocities to predict the detonation velocity of a charge of a massive diameter.
  • Pressure versus scaled distance. A charge of a specific size is detonated and its pressure effects measured at a standard distance. The values obtained are compared with those for TNT.
  • Impulse versus scaled distance. A charge of a specific size is detonated and its impulse (the area under the pressure-time curve) measured as a function of distance. The results are tabulated and expressed as TNT equivalents.
  • Relative bubble energy (RBE). A 5 to 50 kg charge is detonated in water and piezoelectric gauges measure peak pressure, time constant, impulse, and energy.
The RBE may be defined as Kx 3
RBE = Ks
where K = the bubble expansion period for an experimental (x) or a standard (s) charge.


In addition to strength, explosives display a second characteristic, which is their shattering effect or brisance (from the French meaning to “break”), which is distinguished and separate from their total work capacity. This characteristic is of practical importance in determining the effectiveness of an explosion in fragmenting shells, bomb casings, grenades, and the like. The rapidity with which an explosive reaches its peak pressure (power) is a measure of its brisance. Brisance values are primarily employed in France and Russia.

The sand crush test is commonly employed to determine the relative brisance in comparison to TNT. No test is capable of directly comparing the explosive properties of two or more compounds; it is important to examine the data from several such tests (sand crush, trauzl, and so forth) in order to gauge relative brisance. True values for comparison require field experiments.


Density of loading refers to the mass of an explosive per unit volume. Several methods of loading are available, including pellet loading, cast loading, and press loading, the choice being determined by the characteristics of the explosive. Dependent upon the method employed, an average density of the loaded charge can be obtained that is within 80–99% of the theoretical maximum density of the explosive. High load density can reduce sensitivity by making the mass more resistant to internal friction. However, if density is increased to the extent that individual crystals are crushed, the explosive may become more sensitive. Increased load density also permits the use of more explosive, thereby increasing the power of the warhead. It is possible to compress an explosive beyond a point of sensitivity, known also as dead-pressing, in which the material is no longer capable of being reliably initiated, if at all.


Volatility is the readiness with which a substance vaporizes. Excessive volatility often results in the development of pressure within rounds of ammunition and separation of mixtures into their constituents. Volatility affects the chemical composition of the explosive such that a marked reduction in stability may occur, which results in an increase in the danger of handling.

Hygroscopicity and water resistance[edit]

The introduction of water into an explosive is highly undesirable since it reduces the sensitivity, strength, and velocity of detonation of the explosive. Hygroscopicity is used as a measure of a material’s moisture-absorbing tendencies. Moisture affects explosives adversely by acting as an inert material that absorbs heat when vaporized, and by acting as a solvent medium that can cause undesired chemical reactions. Sensitivity, strength, and velocity of detonation are reduced by inert materials that reduce the continuity of the explosive mass. When the moisture content evaporates during detonation, cooling occurs, which reduces the temperature of reaction. Stability is also affected by the presence of moisture since moisture promotes decomposition of the explosive and, in addition, causes corrosion of the explosive’s metal container.

Explosives considerably differ from one another as to their behavior in the presence of water. Gelatin dynamites containing nitroglycerine have a degree of water resistance. Explosives based on ammonium nitrate have little or no water resistance due to the reaction between ammonium nitrate and water, which liberates ammonia, nitrogen dioxide and hydrogen peroxide. In addition, ammonium nitrate is hygroscopic, susceptible to damp, hence the above concerns.


There are many types of explosives which are toxic to some extent. Manufacturing inputs can also be organic compounds or hazardous materials that require special handing due to risks (such as carcinogens). The decomposition products, residual solids or gases of some explosives can be toxic, whereas others are harmless, such as carbon dioxide and water. Examples of harmful by-products are:

  • Heavy metals, such as lead, mercury and barium from primers (observed in high volume firing ranges).
  • Nitric oxides from TNT.
  • Perchlorates when used in large quantities.

“Green explosives” seek to reduce environment and health impacts. An example of such is the lead-free primary explosive copper(I) 5-nitrotetrazolate, an alternative to lead azide.[14] One variety of a green explosive is CDP explosives, whose synthesis does not involve any toxic ingredients, consumes carbon dioxide while detonating and does not release any nitric oxides into the atmosphere when used.

Explosive train[edit]

Explosive material may be incorporated in the explosive train of a device or system. An example is a pyrotechnic lead igniting a booster, which causes the main charge to detonate.

Volume of products of explosion[edit]

The most widely used explosives are condensed liquids or solids converted to gaseous products by explosive chemical reactions and the energy released by those reactions. The gaseous products of complete reaction are typically carbon dioxidesteam, and nitrogen.[15] Gaseous volumes computed by the ideal gas law tend to be too large at high pressures characteristic of explosions.[16] Ultimate volume expansion may be estimated at three orders of magnitude, or one liter per gram of explosive. Explosives with an oxygen deficit will generate soot or gases like carbon monoxide and hydrogen, which may react with surrounding materials such as atmospheric oxygen.[15] Attempts to obtain more precise volume estimates must consider the possibility of such side reactions, condensation of steam, and aqueous solubility of gases like carbon dioxide.[17]

By comparison, CDP detonation is based on the rapid reduction of carbon dioxide to carbon with the abundant release of energy. Rather than produce typical waste gases like carbon dioxide, carbon monoxide, nitrogen and nitric oxides, CDP is different. Instead, the highly energetic reduction of carbon dioxide to carbon vaporizes and pressurizes excess dry ice at the wave front, which is the only gas released from the detonation. The velocity of detonation for CDP formulations can therefore be customized by adjusting the weight percentage of reducing agent and dry ice. Interestingly, CDP detonations produce a large amount of solid materials that can have great commercial value as an abrasive:

Example – CDP Detonation Reaction with Magnesium: XCO2 + 2Mg —-> 2MgO + C + (X-1)CO2

The products of detonation in this example are magnesium oxide, carbon in various phases including diamond, and vaporized excess carbon dioxide that was not consumed by the amount of magnesium in the explosive formulation.[18]

Oxygen balance (OB% or Ω)[edit]

Oxygen balance is an expression that is used to indicate the degree to which an explosive can be oxidized. If an explosive molecule contains just enough oxygen to convert all of its carbon to carbon dioxide, all of its hydrogen to water, and all of its metal to metal oxide with no excess, the molecule is said to have a zero oxygen balance. The molecule is said to have a positive oxygen balance if it contains more oxygen than is needed and a negative oxygen balance if it contains less oxygen than is needed.[19] The sensitivity, strength, and brisance of an explosive are all somewhat dependent upon oxygen balance and tend to approach their maxima as oxygen balance approaches zero.

Oxygen balance applies to traditional explosives mechanics with the assumption that carbon is oxidized to carbon monoxide and carbon dioxide during detonation. In what seems like a paradox to an explosives expert, Cold Detonation Physics uses carbon in its most highly oxidized state as the source of oxygen in the form of carbon dioxide. Oxygen balance, therefore, either does not apply to a CDP formulation or must be calculated without including the carbon in the carbon dioxide.[18]

Chemical composition[edit]

A chemical explosive may consist of either a chemically pure compound, such as nitroglycerin, or a mixture of a fuel and an oxidizer, such as black powder or grain dust and air.

Chemically pure compounds[edit]

Some chemical compounds are unstable in that, when shocked, they react, possibly to the point of detonation. Each molecule of the compound dissociates into two or more new molecules (generally gases) with the release of energy.

  • Nitroglycerin: A highly unstable and sensitive liquid.
  • Acetone peroxide: A very unstable white organic peroxide.
  • TNT: Yellow insensitive crystals that can be melted and cast without detonation.
  • Cellulose nitrate: A nitrated polymer which can be a high or low explosive depending on nitration level and conditions.
  • RDXPETNHMX: Very powerful explosives which can be used pure or in plastic explosives.

The above compositions may describe most of the explosive material, but a practical explosive will often include small percentages of other substances. For example, dynamite is a mixture of highly sensitive nitroglycerin with sawdust, powdered silica, or most commonly diatomaceous earth, which act as stabilizers. Plastics and polymers may be added to bind powders of explosive compounds; waxes may be incorporated to make them safer to handle; aluminium powder may be introduced to increase total energy and blast effects. Explosive compounds are also often “alloyed”: HMX or RDX powders may be mixed (typically by melt-casting) with TNT to form Octol or Cyclotol.

Mixture of oxidizer and fuel[edit]

An oxidizer is a pure substance (molecule) that in a chemical reaction can contribute some atoms of one or more oxidizing elements, in which the fuel component of the explosive burns. On the simplest level, the oxidizer may itself be an oxidizing element, such as gaseous or liquid oxygen.

Availability and cost[edit]

The availability and cost of explosives are determined by the availability of the raw materials and the cost, complexity, and safety of the manufacturing operations.

Classification of explosive materials[edit]

By sensitivity[edit]

Primary explosive[edit]

primary explosive is an explosive that is extremely sensitive to stimuli such as impactfrictionheatstatic electricity, or electromagnetic radiation. Some primary explosives are also known as contact explosives. A relatively small amount of energy is required for initiation. As a very general rule, primary explosives are considered to be those compounds that are more sensitive than PETN. As a practical measure, primary explosives are sufficiently sensitive that they can be reliably initiated with a blow from a hammer; however, PETN can also usually be initiated in this manner, so this is only a very broad guideline. Additionally, several compounds, such as nitrogen triiodide, are so sensitive that they cannot even be handled without detonating. Nitrogen triiodide is so sensitive that it can be reliably detonated by exposure to alpha radiation; it is the only explosive for which this is true.

Primary explosives are often used in detonators or to trigger larger charges of less sensitive secondary explosives. Primary explosives are commonly used in blasting caps and percussion caps to translate a physical shock signal. In other situations, different signals such as electrical/physical shock, or, in the case of laser detonation systems, light, are used to initiate an action, i.e., an explosion. A small quantity, usually milligrams, is sufficient to initiate a larger charge of explosive that is usually safer to handle.

Examples of primary high explosives are:

Secondary explosive[edit]

secondary explosive is less sensitive than a primary explosive and requires substantially more energy to be initiated. Because they are less sensitive, they are usable in a wider variety of applications and are safer to handle and store. Secondary explosives are used in larger quantities in an explosive train and are usually initiated by a smaller quantity of a primary explosive.

Examples of secondary explosives include TNT and RDX.

Tertiary explosive[edit]

Tertiary explosives, also called blasting agents, are so insensitive to shock that they cannot be reliably detonated by practical quantities of primary explosive, and instead require an intermediate explosive booster of secondary explosive. These are often used for safety and the typically lower costs of material and handling. The largest consumers are large-scale mining and construction operations.

ANFO is an example of a tertiary explosive.

By velocity[edit]

Low explosives[edit]

Low explosives are compounds where the rate of decomposition proceeds through the material at less than the speed of sound. The decomposition is propagated by a flame front (deflagration) which travels much more slowly through the explosive material than a shock wave of a high explosiveUnder normal conditions, low explosives undergo deflagration at rates that vary from a few centimetres per second to approximately 400 metres per second. It is possible for them to deflagrate very quickly, producing an effect similar to a detonation. This can happen under higher pressure or temperature, which usually occurs when ignited in a confined space.[citation needed]

A low explosive is usually a mixture of a combustible substance and an oxidant that decomposes rapidly (deflagration); however, they burn more slowly than a high explosive, which has an extremely fast burn rate.[citation needed]

Low explosives are normally employed as propellants. Included in this group are petroleum products such as propane and gasolinegunpowder (both black and smokeless), and light pyrotechnics, such as flares and fireworks, but can replace high explosives in certain applications, see gas pressure blasting.[citation needed]

High explosives[edit]

High explosives (HE) are explosive materials that detonate, meaning that the explosive shock front passes through the material at a supersonic speed. High explosives detonate with explosive velocity ranging from 3 to 9 km/s. For instance, TNT has a detonation (burn) rate of approximately 5.8 km/s (19,000 feet per second), Detonating cord of 6.7 km/s (22,000 feet per second), and C-4 about 8.5 km/s (29,000 feet per second). They are normally employed in mining, demolition, and military applications. They can be divided into two explosives classes differentiated by sensitivityprimary explosive and secondary explosive. The term high explosive is in contrast with the term low explosive, which explodes (deflagrates) at a lower rate. They are stable and quite insensitive to fire and mechanical shocks.

Countless high-explosive compounds are chemically possible, but commercially and militarily important ones have included NGTNT, TNX, RDXHMXPETNTATB, and HNS.

By composition[edit]

Priming composition[edit]

Priming compositions are primary explosives mixed with other compositions to control (lessen) the sensitivity of the mixture to the desired property.

For example, primary explosives are so sensitive that they need to be stored and shipped in a wet state to prevent accidental initiation.

By physical form[edit]

Explosives are often characterized by the physical form that the explosives are produced or used in. These use forms are commonly categorized as:[22]

Shipping label classifications[edit]

Shipping labels and tags may include both United Nations and national markings.

United Nations markings include numbered Hazard Class and Division (HC/D) codes and alphabetic Compatibility Group codes. Though the two are related, they are separate and distinct. Any Compatibility Group designator can be assigned to any Hazard Class and Division. An example of this hybrid marking would be a consumer firework, which is labeled as 1.4G or 1.4S.

Examples of national markings would include United States Department of Transportation (U.S. DOT) codes.

United Nations Organization (UNO) Hazard Class and Division (HC/D)[edit]

Explosives warning sign

The Hazard Class and Division (HC/D) is a numeric designator within a hazard class indicating the character, predominance of associated hazards, and potential for causing personnel casualties and property damage. It is an internationally accepted system that communicates using the minimum amount of markings the primary hazard associated with a substance.[23]

Listed below are the Divisions for Class 1 (Explosives):

  • 1.1 Mass Detonation Hazard. With HC/D 1.1, it is expected that if one item in a container or pallet inadvertently detonates, the explosion will sympathetically detonate the surrounding items. The explosion could propagate to all or the majority of the items stored together, causing a mass detonation. There will also be fragments from the item’s casing and/or structures in the blast area.
  • 1.2 Non-mass explosion, fragment-producing. HC/D 1.2 is further divided into three subdivisions, HC/D 1.2.1, 1.2.2 and 1.2.3, to account for the magnitude of the effects of an explosion.
  • 1.3 Mass fire, minor blast or fragment hazard. Propellants and many pyrotechnic items fall into this category. If one item in a package or stack initiates, it will usually propagate to the other items, creating a mass fire.
  • 1.4 Moderate fire, no blast or fragment. HC/D 1.4 items are listed in the table as explosives with no significant hazard. Most small arms ammunition (including loaded weapons) and some pyrotechnic items fall into this category. If the energetic material in these items inadvertently initiates, most of the energy and fragments will be contained within the storage structure or the item containers themselves.
  • 1.5 mass detonation hazard, very insensitive.
  • 1.6 detonation hazard without mass detonation hazard, extremely insensitive.

To see an entire UNO Table, browse Paragraphs 3-8 and 3-9 of NAVSEA OP 5, Vol. 1, Chapter 3.

Class 1 Compatibility Group[edit]

Compatibility Group codes are used to indicate storage compatibility for HC/D Class 1 (explosive) materials. Letters are used to designate 13 compatibility groups as follows.

A: Primary explosive substance (1.1A).

B: An article containing a primary explosive substance and not containing two or more effective protective features. Some articles, such as detonator assemblies for blasting and primers, cap-type, are included. (1.1B, 1.2B, 1.4B).

C: Propellant explosive substance or other deflagrating explosive substance or article containing such explosive substance (1.1C, 1.2C, 1.3C, 1.4C). These are bulk propellants, propelling charges, and devices containing propellants with or without means of ignition. Examples include single-based propellant, double-based propellant, triple-based propellant, and composite propellantssolid propellant rocket motors and ammunition with inert projectiles.

D: Secondary detonating explosive substance or black powder or article containing a secondary detonating explosive substance, in each case without means of initiation and without a propelling charge, or article containing a primary explosive substance and containing two or more effective protective features. (1.1D, 1.2D, 1.4D, 1.5D).

E: Article containing a secondary detonating explosive substance without means of initiation, with a propelling charge (other than one containing flammable liquid, gel or hypergolic liquid) (1.1E, 1.2E, 1.4E).

F containing a secondary detonating explosive substance with its means of initiation, with a propelling charge (other than one containing flammable liquid, gel or hypergolic liquid) or without a propelling charge (1.1F, 1.2F, 1.3F, 1.4F).

G: Pyrotechnic substance or article containing a pyrotechnic substance, or article containing both an explosive substance and an illuminating, incendiary, tear-producing or smoke-producing substance (other than a water-activated article or one containing white phosphorus, phosphide or flammable liquid or gel or hypergolic liquid) (1.1G, 1.2G, 1.3G, 1.4G). Examples include Flares, signals, incendiary or illuminating ammunition and other smoke and tear producing devices.

H: Article containing both an explosive substance and white phosphorus (1.2H, 1.3H). These articles will spontaneously combust when exposed to the atmosphere.

J: Article containing both an explosive substance and flammable liquid or gel (1.1J, 1.2J, 1.3J). This excludes liquids or gels which are spontaneously flammable when exposed to water or the atmosphere, which belong in group H. Examples include liquid or gel filled incendiary ammunition, fuel-air explosive (FAE) devices, and flammable liquid fueled missiles.

K: Article containing both an explosive substance and a toxic chemical agent (1.2K, 1.3K)

L Explosive substance or article containing an explosive substance and presenting a special risk (e.g., due to water-activation or presence of hypergolic liquids, phosphides, or pyrophoric substances) needing isolation of each type (1.1L, 1.2L, 1.3L). Damaged or suspect ammunition of any group belongs in this group.

N: Articles containing only extremely insensitive detonating substances (1.6N).

S: Substance or article so packed or designed that any hazardous effects arising from accidental functioning are limited to the extent that they do not significantly hinder or prohibit fire fighting or other emergency response efforts in the immediate vicinity of the package (1.4S).


The legality of possessing or using explosives varies by jurisdiction. Various countries around the world have enacted explosives law and require licenses to manufacture, distribute, store, use, possess explosives or ingredients.


In the Netherlands, the civil and commercial use of explosives is covered under the Wet explosieven voor civiel gebruik (explosives for civil use Act), in accordance with EU directive nr. 93/15/EEG[24] (Dutch). The illegal use of explosives is covered under the Wet Wapens en Munitie (Weapons and Munition Act)[25] (Dutch).


United States[edit]

During World War I, numerous laws were created to regulate war related industries and increase security within the United States. In 1917, the 65th United States Congress created many laws, including the Espionage Act of 1917 and Explosives Act of 1917.

The Explosives Act of 1917 (session 1, chapter 83, 40 Stat. 385) was signed on 6 October 1917 and went into effect on 16 November 1917. The legal summary is “An Act to prohibit the manufacture, distribution, storage, use, and possession in time of war of explosives, providing regulations for the safe manufacture, distribution, storage, use, and possession of the same, and for other purposes”. This was the first federal regulation of licensing explosives purchases. The act was deactivated after World War I ended.[26]

After the United States entered World War II, the Explosives Act of 1917 was reactivated. In 1947, the act was deactivated by President Truman.[27]

The Organized Crime Control Act of 1970 (Pub.L. 91–452) transferred many explosives regulations to the Bureau of Alcohol, Tobacco and Firearms (ATF) of the Department of Treasury. The bill became effective in 1971.[28]

Currently, regulations are governed by Title 18 of the United States Code and Title 27 of the Code of Federal Regulations:

  • “Importation, Manufacture, Distribution and Storage of Explosive Materials” (18 U.S.C. Chapter 40).[29]
  • “Commerce in Explosives” (27 C.F.R. Chapter II, Part 555).[30]

State laws[edit]

List of explosives[edit]









Yet to be sorted[edit]



See also[edit]


  1. Jump up^ Sastri, M.N. (2004). Weapons of Mass Destruction. APH Publishing Corporation. p. 1. ISBN 978-8176487429.
  2. Jump up^ Singh, Kirpal (2010). Chemistry in Daily Life. Prentice-Hall. p. 68. ISBN 978-8120346178.
  3. Jump up^ Sigurðsson, Albert (17 January 2017). “China’s explosive history of gunpowder and fireworks”GB TimesArchivedfrom the original on 1 December 2017.
  4. Jump up^ Pomeranz, Ken; Wong, Bin. “China and Europe, 1500–2000 and Beyond: What is Modern?” (PDF). 2004: Columbia University Press. Archived (PDF) from the original on 13 December 2016.
  5. Jump up^ Kerr, Gordon (2013). A Short History of China. No Exit Press. ISBN 978-1-84243-968-5.
  6. Jump up^ Takacs, Sarolta Anna; Cline, Eric H. (2008). The Ancient World. Routledge. p. 544.
  7. Jump up^ Back, Fiona (2011). p. 55. ISBN 978-1-86397-826-2. Missing or empty |title= (help)
  8. Jump up^ Ankony, Robert C., Lurps: A Ranger’s Diary of Tet, Khe Sanh, A Shau, and Quang Tri, revised ed., Rowman & Littlefield Publishing Group, Lanham, MD (2009), p.73.
  9. Jump up^ W. W. Porterfield, Inorganic Chemistry: A Unified Approach, 2nd ed., Academic Press, Inc., San Diego, pp. 479-480 (1993).
  10. Jump up^ “Archived copy”Archived from the original on 6 February 2017. Retrieved 5 February 2017. | 2.1 Deflagration | Retrieved 05 February 2017
  11. Jump up^ “Archived copy”Archived from the original on 6 February 2017. Retrieved 5 February 2017. | 2.2 Detonation | Retrieved 05 February 2017
  12. Jump up^ Krehl, Peter O. K. (24 September 2008). History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference. Springer Science & Business Media. p. 106. ISBN 978-3-540-30421-0Archived from the original on 24 December 2017.
  13. Jump up^ Krehl, Peter O. K. (2008). History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference. Springer Science & Business Media. p. 1970. ISBN 978-3-540-30421-0.
  14. Jump up^ “Green explosive is a friend of the Earth”. New Scientist. 27 March 2006. Archived from the original on 12 November 2014. Retrieved 12 November 2014.
  15. Jump up to:a b Zel’dovich, Yakov; Kompaneets, A.S. (1960). Theory of Detonation. Academic Press. pp. 208–210.
  16. Jump up^ Hougen, Olaf A.; Watson, Kenneth; Ragatz, Roland (1954). Chemical Process Principles. John Wiley & Sons. pp. 66–67.
  17. Jump up^ Anderson, H.V. (1955). Chemical Calculations. McGraw-Hill. p. 206.
  18. Jump up to:a b c Office, Government of Canada, Industry Canada, Office of the Deputy Minister, Canadian Intellectual Property. “Canadian Patent Database / Base de données sur les brevets canadiens”brevets-patents.ic.gc.caArchived from the original on 18 October 2016. Retrieved 17 October 2016.
  19. Jump up^ Meyer, Rudolf; Josef Köhler; Axel Homburg (2007). Explosives, 6th Ed. Wiley VCH. ISBN 3-527-31656-6.
  20. Jump up^ Sam Barros. “PowerLabs Lead Picrate Synthesis”Archived from the original on 22 May 2016.
  21. Jump up^ Robert Matyáš, Jiří Pachman. Primary Explosives. Springer-Verlag Berlin Heidelberg, 2013. pp 331
  22. Jump up^ Cooper, Paul W. (1996). “Chapter 4: Use forms of explosives”. Explosives Engineering. Wiley-VCH. pp. 51–66. ISBN 0-471-18636-8.
  23. Jump up^ Table 12-4.—United Nations Organization Hazard ClassesArchived 5 June 2010 at the Wayback Machine.. Retrieved on 2010-02-11.
  24. Jump up^ “ – Wet- en regelgeving – Wet explosieven voor civiel gebruik – BWBR0006803”Archived from the original on 25 December 2013.
  25. Jump up^ “ – Wet- en regelgeving – Wet wapens en munitie – BWBR0008804”Archived from the original on 25 December 2013.
  26. Jump up^ “1913 – 1919”Archived from the original on 1 February 2016.
  27. Jump up^ “1940 – 1949”Archived from the original on 4 March 2016.
  28. Jump up^ “1970 – 1979”Archived from the original on 17 November 2015.
  29. Jump up^ “Federal Explosives Laws” (PDF). U.S. Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives. Archived (PDF) from the original on 6 March 2016. Retrieved 1 February 2016.
  30. Jump up^ “Archived copy”Archived from the original on 15 December 2014. Retrieved 13 December 2014. ATF Regulations
  31. Jump up^ “ACASLogin”Archived from the original on 8 December 2014.
  32. Jump up^ “Document – Folio Infobase”Archived from the original on 20 December 2014.
  33. Jump up^ Special provisions relating to black powder Archived 5 June 2010 at the Wayback Machine.

Further reading[edit]

U.S. Government
  • Explosives and Demolitions FM 5-250; U.S. Department of the Army; 274 pages; 1992.
  • Military Explosives TM 9-1300-214; U.S. Department of the Army; 355 pages; 1984.
  • Explosives and Blasting Procedures Manual; U.S. Department of Interior; 128 pages; 1982.
  • Safety and Performance Tests for Qualification of Explosives; Commander, Naval Ordnance Systems Command; NAVORD OD 44811. Washington, D.C.: GPO, 1972.
  • Weapons Systems Fundamentals; Commander, Naval Ordnance Systems Command. NAVORD OP 3000, vol. 2, 1st rev. Washington, D.C.: GPO, 1971.
  • Elements of Armament Engineering – Part One; Army Research Office. Washington, D.C.: U.S. Army Materiel Command, 1964.
  • Hazardous Materials Transportation Plaecards; USDOT.
Institute of Makers of Explosives
Other Historical

External links[edit]

Navigation menu




From Wikipedia, the free encyclopedia
  (Redirected from Tnt)
solid trinitrotoluene
Preferred IUPAC name

Other names

3D model (JSmol)
Abbreviations TNT
ECHA InfoCard 100.003.900
EC Number 204-289-6
PubChem CID
RTECS number XU0175000
UN number 0209 – Dry or wetted with < 30% water
0388, 0389 – Mixtures with trinitrobenzene, hexanitrostilbene
Molar mass 227.13 g·mol−1
Appearance Pale yellow solid. Loose “needles”, flakes or prillsbefore melt-casting. A solid block after being poured into a casing.
Density 1.654 g/cm3
Melting point 80.35 °C (176.63 °F; 353.50 K)
Boiling point 240.0 °C (464.0 °F; 513.1 K) (decomposes)[1]
0.13 g/L (20 °C)
Solubility in etheracetonebenzenepyridine soluble
Vapor pressure 0.0002 mmHg (20°C)[2]
Explosive data
Shock sensitivity Insensitive
Friction sensitivity Insensitive to 353 N
Detonation velocity 6900 m/s
RE factor 1.00
Safety data sheet ICSC 0967
Explosive E ExplosiveToxic T Toxic

Dangerous for the Environment (Nature) N Dangerous for the environment

R-phrases(outdated) R2R23/24/25R33R51/53
S-phrases(outdated) (S1/2)S35S45S61
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g., nitroglycerin Special hazards (white): no code

NFPA 704 four-colored diamond

Lethal dose or concentration (LDLC):
LD50 (median dose)
795 mg/kg (rat, oral)
660 (mouse, oral)[3]
500 mg/kg (rabbit, oral)
1850 mg/kg (cat, oral)[3]
US health exposure limits (NIOSH):
TWA 1.5 mg/m3 [skin][2]
TWA 0.5 mg/m3 [skin][2]
IDLH (Immediate danger)
500 mg/m3[2]
Related compounds
Related compounds
picric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 verify (what is Yes ?)
Infobox references

Trinitrotoluene (/ˌtrˌntrˈtɒljuːˌn, –ljəˌwn/;[4][5] TNT), or more specifically 2,4,6-trinitrotoluene, is a chemical compound with the formula C6H2(NO2)3CH3. This yellow solid is sometimes used as a reagent in chemical synthesis, but it is best known as an explosive material with convenient handling properties. The explosive yield of TNT is considered to be the standard measure of bombs and other explosives. In chemistry, TNT is used to generate charge transfer salts.


Chunks of explosives-grade TNT

Trinitrotoluene melting at 81 °C

M107 artillery shells. All are labelled to indicate a filling of “Comp B” (mixture of TNT and RDX) and have fuzes fitted

Analysis of TNT production by branch of the German army between 1941 and the first quarter of 1944 shown in thousands of tons per month

Detonation of the 500-ton TNT explosive charge as part of Operation Sailor Hat in 1965. The white blast-wave is visible on the water surface and a shock condensation cloud is visible overhead.

World War I-era HE artillery shell for a 9.2 inch howitzer. The red band of copper at the lower part of the grenade is called a belt or girdle. The green band (marked “Trotyl”) indicates that the grenade is blind or use as exercise. Coloring of sharp fired grenades may vary depending on country, etc. Yellow ring is common too sharp and red for older projectiles, etc. Blue = Exercise, White = Phosphorus, Gray = Smoke

TNT was first prepared in 1863 by German chemist Julius Wilbrand[6] and originally used as a yellow dye. Its potential as an explosive was not appreciated for several years, mainly because it was so difficult to detonate and because it was less powerful than alternatives. Its explosive properties were first discovered by another German chemist, Carl Häussermann, in 1891.[7] TNT can be safely poured when liquid into shell cases, and is so insensitive that it was exempted from the UK’s Explosives Act 1875 and was not considered an explosive for the purposes of manufacture and storage.[8]

The German armed forces adopted it as a filling for artillery shells in 1902. TNT-filled armour-piercing shells would explode after they had penetrated the armour of British capital ships, whereas the British lyddite-filled shells tended to explode upon striking armour, thus expending much of their energy outside the ship.[8] The British started replacing lyddite with TNT in 1907.

The United States Navy continued filling armor-piercing shells with explosive D after some other nations had switched to TNT; but began filling naval minesbombsdepth charges, and torpedo warheads with burster charges of crude grade B TNT with the color of brown sugar and requiring an explosive booster charge of granular crystallized grade A TNT for detonation. High-explosive shells were filled with grade A TNT, which became preferred for other uses as industrial chemical capacity became available for removing xylene and similar hydrocarbons from the toluene feedstock and other nitrotoluene isomer byproducts from the nitrating reactions.[9]


In industry, TNT is produced in a three-step process. First, toluene is nitrated with a mixture of sulfuric and nitric acid to produce mononitrotoluene (MNT). The MNT is separated and then renitrated to dinitrotoluene (DNT). In the final step, the DNT is nitrated to trinitrotoluene (TNT) using an anhydrous mixture of nitric acid and oleum. Nitric acid is consumed by the manufacturing process, but the diluted sulfuric acid can be reconcentrated and reused. After nitration, TNT is stabilized by a process called sulfitation, where the crude TNT is treated with aqueous sodium sulfite solution to remove less stable isomers of TNT and other undesired reaction products. The rinse water from sulfitation is known as red water and is a significant pollutant and waste product of TNT manufacture.[10]

Control of nitrogen oxides in feed nitric acid is very important because free nitrogen dioxide can result in oxidation of the methyl group of toluene. This reaction is highly exothermic and carries with it the risk of a runaway reaction leading to an explosion.

In the laboratory, 2,4,6-trinitrotoluene is produced by a two-step process. A nitrating mixture of concentrated nitric and sulfuric acids is used to nitrate toluene to a mixture of mono- and di-nitrotoluene isomers, with careful cooling to maintain temperature. The nitrated toluenes are then separated, washed with dilute sodium bicarbonate to remove oxides of nitrogen, and then carefully nitrated with a mixture of fuming nitric acid and sulfuric acid. Towards the end of the nitration, the mixture is heated on a steam bath. The trinitrotoluene is separated, washed with a dilute solution of sodium sulfite and then recrystallized from alcohol.


TNT is one of the most commonly used explosives for military, industrial, and mining applications. TNT has been used in conjunction with hydraulic fracturing, a process used to recover oil and gas from shale formations. The technique involves displacing and detonating nitroglycerin in hydraulically induced fractures followed by wellbore shots using pelletized TNT.[11]

TNT is valued partly because of its insensitivity to shock and friction, with reduced risk of accidental detonation compared to more sensitive explosives such as nitroglycerin. TNT melts at 80 °C (176 °F), far below the temperature at which it will spontaneously detonate, allowing it to be poured or safely combined with other explosives. TNT neither absorbs nor dissolves in water, which allows it to be used effectively in wet environments. To detonate, TNT must be triggered by a pressure wave from a starter explosive, called an explosive booster.

Although blocks of TNT are available in various sizes (e.g. 250 g, 500 g, 1,000 g), it is more commonly encountered in synergistic explosive blends comprising a variable percentage of TNT plus other ingredients. Examples of explosive blends containing TNT include:

Explosive character[edit]

Upon detonation, TNT decomposes as follows:

2 C7H5N3O6 → 3 N2 + 5 H2O + 7 CO + 7 C
2 C7H5N3O6 → 3 N2 + 5 H2 + 12 CO + 2 C

The reaction is exothermic but has a high activation energy in the gas phase (~62 kcal/mol). The condensed phases (solid or liquid) show markedly lower activation energies of roughly 35 kcal/mol due to unique bimolecular decomposition routes at elevated densities.[20] Because of the production of carbon, TNT explosions have a sooty appearance. Because TNT has an excess of carbon, explosive mixtures with oxygen-rich compounds can yield more energy per kilogram than TNT alone. During the 20th century, amatol, a mixture of TNT with ammonium nitrate was a widely used military explosive.

TNT can be detonated with a high velocity initiator or by efficient concussion.[21] For many years, TNT used to be the reference point for the Figure of Insensitivity. TNT had a rating of exactly 100 on the “F of I” scale. The reference has since been changed to a more sensitive explosive called RDX, which has an F of I rating of 80.

Energy content[edit]

Cross-sectional view of Oerlikon 20 mm cannon shells (dating from circa 1945) showing color codes for TNT and pentolite fillings

The heat of detonation utilized by NIST is 4184 J/g (4.184 MJ/kg).[22] The energy density of TNT is used as a reference-point for many other explosives, including nuclear weapons, the energy content of which is measured in equivalent kilotons (~4.184 terajoules) or megatons (~4.184 petajoules) of TNT. The heat of combustion is 14.5 megajoules per kilogram, which requires that some of the carbon in TNT react with atmospheric oxygen, which does not occur in the initial event.[23]

For comparison, gunpowder contains 3 megajoules per kilogram, dynamite contains 7.5 megajoules per kilogram, and gasoline contains 47.2 megajoules per kilogram (though gasoline requires an oxidant, so an optimized gasoline and O2 mixture contains 10.4 megajoules per kilogram).


Various methods can be used to detect TNT including optical and electrochemical sensors and explosive-sniffing dogs. In 2013, researchers from the Indian Institutes of Technology using noble-metal quantum clusters could detect TNT at the sub-zeptomolar (10−18 mol/m3) level.[24]

Safety and toxicity[edit]

TNT is poisonous, and skin contact can cause skin irritation, causing the skin to turn a bright yellow-orange color. During the First World War, munition workers who handled the chemical found that their skin turned bright yellow, which resulted in their acquiring the nickname “canary girls” or simply “canaries.”

People exposed to TNT over a prolonged period tend to experience anemia and abnormal liver functions. Blood and liver effects, spleen enlargement and other harmful effects on the immune system have also been found in animals that ingested or breathed trinitrotoluene. There is evidence that TNT adversely affects male fertility.[25] TNT is listed as a possible human carcinogen, with carcinogenic effects demonstrated in animal experiments (rat), although effects upon humans so far amount to none [according to IRIS of March 15, 2000].[26] Consumption of TNT produces red urine through the presence of breakdown products and not blood as sometimes believed.[27]

Some military testing grounds are contaminated with TNT. Wastewater from munitions programs including contamination of surface and subsurface waters may be colored pink because of the presence of TNT. Such contamination, called “pink water“, may be difficult and expensive to remedy.

TNT is prone to exudation of dinitrotoluenes and other isomers of trinitrotoluene. Even small quantities of such impurities can cause such effect. The effect shows especially in projectiles containing TNT and stored at higher temperatures, e.g. during summer. Exudation of impurities leads to formation of pores and cracks (which in turn cause increased shock sensitivity). Migration of the exudated liquid into the fuze screw thread can form fire channels, increasing the risk of accidental detonations; fuze malfunction can result from the liquids migrating into its mechanism.[28] Calcium silicate is mixed with TNT to mitigate the tendency towards exudation.[29]

Ecological impact[edit]

Because of its use in construction and demolition, TNT has become the most widely used explosive, and thus its toxicity is the most characterized and reported. Residual TNT from manufacture, storage, and use can pollute water, soil, atmosphere, and biosphere.

The concentration of TNT in contaminated soil can reach 50 g/kg of soil, where the highest concentrations can be found on or near the surface. In the last decade[when?], the United States Environmental Protection Agency (USEPA) has declared TNT a pollutant whose removal is priority.[30] The USEPA maintains that TNT levels in soil should not exceed 17.2 gram per kilogram of soil and 0.01 milligrams per liter of water.[31]

Aqueous solubility[edit]

Dissolution is a measure of the rate that solid TNT in contact with water is dissolved. The relatively low aqueous solubility of TNT causes the dissolution of solid particles to be continuously released to the environment over extended periods of time.[32] Studies have shown that the TNT dissolved slower in saline water than in freshwater. However, when salinity was altered, TNT dissolved at the same speed (Figure 2).[33] Because TNT is moderately soluble in water, it can migrate through subsurface soil, and cause groundwater contamination.[34]

Soil adsorption[edit]

Adsorption is a measure of the distribution between soluble and sediment adsorbed contaminants following attainment of equilibrium. TNT and its transformation products are known to adsorb to surface soils and sediments, where they undergo reactive transformation or remained stored.[35] The movement or organic contaminants through soils is a function of their ability to associate with the mobile phase (water) and a stationary phase (soil). Materials that associate strongly with soils move slowly through soil. Materials that associate strongly with water move through water with rates approaching that of ground water movement.

The association constant for TNT with a soil is 2.7 to 11 liters per kilogram of soil.[36] This means that TNT has a one- to tenfold tendency to adhere to soil particulates than not when introduced into the soil.[32] Hydrogen bonding and ion exchange are two suggested mechanisms of adsorption between the nitro functional groups and soil colloids.

The number of functional groups on TNT influences the ability to adsorb into soil. Adsorption coefficient values have been shown to increase with an increase in the number of amino groups. Thus, adsorption of the TNT decomposition product 2,4-diamino-6-nitrotoluene (2,4-DANT) was greater than that for 4-amino-2,6-dinitrotoluene (4-ADNT), which was greater than that for TNT.[32] Lower adsorption coefficients for 2,6-DNT compared to 2,4-DNT can be attributed to the steric hindrance of the NO3 group in the ortho position.

Research has shown that in freshwater environments, with a high abundances of Ca2+, the adsorption of TNT and its transformation products to soils and sediments may be lower than observed in a saline environment, dominated by K+ and Na+. Therefore, when considering the adsorption of TNT, the type of soil or sediment and the ionic composition and strength of the ground water are important factors.[37]

The association constants for TNT and its degradation products with clays have been determined. Clay minerals have a significant effect on the adsorption of energetic compounds. Soil properties, such as organic carbon content and cation exchange capacity had significant impacts of the adsorption coefficients reported in the table below.

Additional studies have shown that the mobility of TNT degradation products is likely to be lower “than TNT in subsurface environments where specific adsorption to clay minerals dominates the sorption process.”[37] Thus, the mobility of TNT and its transformation products are dependent on the characteristics of the sorbent.[37] The mobility of TNT in groundwater and soil has been extrapolated from “sorption and desorption isotherm modelsdetermined with humic acids, in aquifer sediments, and soils”.[37] From these models, it is predicted that TNT has a low retention and transports readily in the environment.[30]

Compared to other explosives, TNT has a higher association constant with soil, meaning it adheres more with soil than with water. Conversely, other explosives, such as RDX and HMX with low association constants (ranging from 0.06 to 7.3 L/kg and 0 to 1.6 L/kg respectively) can move more rapidly in water.[32]

Chemical breakdown[edit]

TNT is a reactive molecule and is particularly prone to react with reduced components of sediments or photodegradation in the presence of sunlight. TNT is thermodynamically and kinetically capable of reacting with a wide number of components of many environmental systems. This includes wholly abiotic reactants, like photonshydrogen sulfideFe2+, or microbial communities, both oxic and anoxic.

Soils with high clay contents or small particle sizes and high total organic carbon content have been shown to promote TNT transformation. Possible TNT transformations include reduction of one, two, or three nitro-moieties to amines and coupling of amino transformation products to form dimers. Formation of the two monoamino transformation products, 2-ADNT and 4-ADNT are energetically favored, and therefore are observed in contaminated soils and ground water. The diamino products are energetically less favorable, and even less likely are the triamino products.

The transformation of TNT is significantly enhanced under anaerobic conditions as well as under highly reducing conditions. TNT transformations in soils can occur both biologically and abiotically.[37]

Photolysis is a major process that impacts the transformation of energetic compounds. The alteration of a molecule in photolysis occurs in the presence of direct absorption of light energy by the transfer of energy from a photosensitized compound. Phototransformation of TNT “results in the formation of nitrobenzenesbenzaldehydes, azodicarboxylic acids, and nitrophenols, as a result of the oxidation of methyl groups, reduction of nitro groups, and dimer formation.”[32]

Evidence of the photolysis of TNT has been seen due to the color change to pink of the wastewaters when exposed to sunlight. Photolysis was more rapid in river water than in distilled water. Ultimately, photolysis affects the fate of TNT primarily in the aquatic environment but could also affect the reaction when exposed to sunlight on the soil surface.[37]


The ligninolytic physiological phase and manganese peroxidase system of fungi can cause a very limited amount of mineralization of TNT in a liquid culture; though not in soil. An organism capable of the remediation of large amounts of TNT in soil has yet to be discovered.[38] Both wild and transgenic plants can phytoremediate explosives from soil and water.[39]

See also[edit]


  1. Jump up^ 2,4,6-Trinitrotoluene.
  2. Jump up to:a b c d “NIOSH Pocket Guide to Chemical Hazards #0641”National Institute for Occupational Safety and Health (NIOSH).
  3. Jump up to:a b “2,4,6-Trinitrotoluene”Immediately Dangerous to Life and Health Concentrations (IDLH)National Institute for Occupational Safety and Health (NIOSH).
  4. Jump up^ “Trinitrotoluene”Merriam-Webster Dictionary.
  5. Jump up^ “Trinitrotoluene” UnabridgedRandom House.
  6. Jump up^ Wilbrand, J. (1863). “Notiz über Trinitrotoluol”Annalen der Chemie und Pharmacie128 (2): 178–179. doi:10.1002/jlac.18631280206.
  7. Jump up^ Peter O. K. Krehl (2008). History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference. Springer Science & Business Media. p. 404. ISBN 978-3-540-30421-0.
  8. Jump up to:a b Brown GI (1998). The Big Bang: a History of Explosives. Sutton Publishing. pp. 151–153. ISBN 0-7509-1878-0.
  9. Jump up^ Fairfield AP (1921). Naval Ordnance. Lord Baltimore Press. pp. 49–52.
  10. Jump up^ Urbanski T (1964). Chemistry and Technology of Explosives1. Pergamon Press. pp. 389–91. ISBN 0-08-010238-7.
  11. Jump up^ Miller, J. S.; Johansen, R. T. (1976). “Fracturing Oil Shale with Explosives for In Situ Recovery” (PDF). Shale Oil, Tar Sand and Related Fuel SourcesAmerican Chemical Society: 151. Retrieved 27 March 2015.
  12. Jump up^ Campbell J (1985). Naval weapons of World War Two. London: Conway Maritime Press. p. 100. ISBN 978-0-85177-329-2.
  13. Jump up^ U.S. Explosive Ordnance, Bureau of Ordnance. Washington, D.C.: U.S. Department of the Navy. 1947. p. 580.
  14. Jump up^ Explosives – Compounds
  15. Jump up^ Military Specification MIL-C-401
  16. Jump up^ Cooper PW (1996). Explosives Engineering. Wiley-VCH. ISBN 0-471-18636-8.
  17. Jump up^ DEPARTMENT OF THE TREASURY:Bureau of Alcohol, Tobacco and Firearms Retrieved 2011-12-02
  18. Jump up^ [secondary source] webpages:submarine torpedo explosive Retrieved 2011-12-02
  19. Jump up^ website showing copy of a North American Intelligence document see:page 167 Retrieved 2011-12-02
  20. Jump up^ Furman et al. (2014), Decomposition of Condensed Phase Energetic Materials: Interplay between Uni- and Bimolecular Mechanisms, J. Am. Chem. Soc., 2014, 136 (11), pp 4192–4200.
  21. Jump up^ Merck Index, 13th Edition, 9801
  22. Jump up^ NIST Guide for the Use of the International System of Units (SI): Appendix B8—Factors for Units Listed Alphabetically
  23. Jump up^ Babrauskas, Vytenis (2003). Ignition Handbook. Issaquah, WA: Fire Science Publishers/Society of Fire Protection Engineers. p. 453. ISBN 0-9728111-3-3.
  24. Jump up^ Grad, Paul (April 2013). “Quantum clusters serve as ultra-sensitive detectors”Chemical Engineering.
  25. Jump up^ Toxicological Profile for 2,4,6-Trinitrotoluene.
  26. Jump up^ from U.S. Environmental Protection Agency’s Integrated Risk Information System (IRIS) within the NLM Hazardous Substances Databank – Trinitrotoluene
  27. Jump up^ “2,4,6-Trinitrotoluene” (PDF). Agency for Toxic Substances and Disease Registry. Retrieved 2010-05-17.
  28. Jump up^ Akhavan J (2004). The Chemistry of Explosives. Royal Society of Chemistry. pp. 11–. ISBN 978-0-85404-640-9.
  29. Jump up^ “Explosive & Propellant Additives”
  30. Jump up to:a b Esteve-Núñez A, Caballero A, Ramos JL (2001). “Biological degradation of 2,4,6-trinitrotoluene”Microbiol. Mol. Biol. Rev65 (3): 335–52, table of contents. doi:10.1128/MMBR.65.3.335-352.2001PMC 99030Freely accessiblePMID 11527999.
  31. Jump up^ Ayoub K, van Hullebusch ED, Cassir M, Bermond A (2010). “Application of advanced oxidation processes for TNT removal: A review”. J. Hazard. Mater178 (1-3): 10–28. doi:10.1016/j.jhazmat.2010.02.042PMID 20347218.
  32. Jump up to:a b c d e Pichte J (2012). “Distribution and Fate of Military Explosives and Propellants in Soil: A Review”. Applied and Environmental Soil Science2012: 1–33. doi:10.1155/2012/617236.
  33. Jump up^ Brannon JM, Price CB, Yost SL, Hayes C, Porter B (2005). “Comparison of environmental fate and transport process descriptors of explosives in saline and freshwater systems”. Mar. Pollut. Bull50 (3): 247–51. doi:10.1016/j.marpolbul.2004.10.008PMID 15757688.
  34. Jump up^ Halasz A, Groom C, Zhou E, Paquet L, Beaulieu C, Deschamps S, Corriveau A, Thiboutot S, Ampleman G, Dubois C, Hawari J (2002). “Detection of explosives and their degradation products in soil environments”. J Chromatogr A963 (1-2): 411–8. PMID 12187997.
  35. Jump up^ Douglas TA, Johnson L, Walsh M, Collins C (2009). “A time series investigation of the stability of nitramine and nitroaromatic explosives in surface water samples at ambient temperature”. Chemosphere76 (1): 1–8. doi:10.1016/j.chemosphere.2009.02.050PMID 19329139.
  36. Jump up^ Haderlein SB, Weissmahr KW, Schwarzenbach RP (January 1996). “Specific Adsorption of Nitroaromatic Explosives and Pesticides to Clay Minerals”. Environmental Science & Technology30 (2): 612–622. doi:10.1021/es9503701.
  37. Jump up to:a b c d e f Pennington JC, Brannon JM (February 2002). “Environmental fate of explosives”. Thermochimica Acta384 (1-2): 163–172. doi:10.1016/S0040-6031(01)00801-2.
  38. Jump up^ Hawari J, Beaudet S, Halasz A, Thiboutot S, Ampleman G (2000). “Microbial degradation of explosives: biotransformation versus mineralization”. Appl. Microbiol. Biotechnol54 (5): 605–18. doi:10.1007/s002530000445PMID 11131384.
  39. Jump up^ Panz K, Miksch K (2012). “Phytoremediation of explosives (TNT, RDX, HMX) by wild-type and transgenic plants”. J. Environ. Manage113: 85–92. doi:10.1016/j.jenvman.2012.08.016PMID 22996005.

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