Nitrogen trichloride

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Nitrogen trichloride
Structural formula of nitrogen trichloride NCl3 dimensions.svg
Structural formula of nitrogen trichloride
Space-filling model of nitrogen trichloride Nitrogen-trichloride-3D-vdW.png
Space-filling model of nitrogen trichloride
Nitrogen trichloride.JPG
Other names
Nitrogen(III) chloride
Trichlorine nitride
3D model (JSmol)
ECHA InfoCard 100.030.029 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-045-1
PubChem CID
RTECS number
  • QW974000
  • InChI=1S/Cl3N/c1-4(2)3 Yes check.svgY
  • InChI=1/Cl3N/c1-4(2)3
  • ClN(Cl)Cl
Appearanceyellow oily liquid
Odor chlorine-like
Density 1.653 g/mL
Melting point −40 °C (−40 °F; 233 K)
Boiling point 71 °C (160 °F; 344 K)
slowly decomposes
Solubility soluble in benzene, chloroform, CCl4, CS2, PCl3
orthorhombic (below −40 °C)
trigonal pyramidal
0.6 D
232 kJ/mol
NFPA 704 (fire diamond)
93 °C (199 °F; 366 K)
Related compounds
Other anions
Nitrogen trifluoride
Nitrogen tribromide
Nitrogen triiodide
Other cations
Phosphorus trichloride
Arsenic trichloride
Related chloramines
Related compounds
Nitrosyl chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Nitrogen trichloride, also known as trichloramine, is the chemical compound with the formula NCl3. This yellow, oily, pungent-smelling and explosive liquid is most commonly encountered as a byproduct of chemical reactions between ammonia-derivatives and chlorine (for example, in swimming pools). Alongside monochloramine and dichloramine, trichloramine is responsible for the distinctive 'chlorine smell' associated with swimming pools, where the compound is readily formed as a product from hypochlorous acid reacting with ammonia and other nitrogenous substances in the water, such as urea from urine. [1]


Preparation and structure

The compound is prepared by treatment of ammonium salts, such as ammonium nitrate with chlorine.

Intermediates in this conversion include monochloramine and dichloramine, NH2Cl and NHCl2, respectively.

Like ammonia, NCl3 is a pyramidal molecule. The N-Cl distances are 1.76 Å, and the Cl-N-Cl angles are 107°. [2]

Reactions and uses

The chemistry of NCl3 has been well explored. [3] It is moderately polar with a dipole moment of 0.6 D. The nitrogen center is basic but much less so than ammonia. It is hydrolyzed by hot water to release ammonia and hypochlorous acid.

NCl3 + 3 H2O → NH3 + 3 HOCl

NCl3 explodes to give N2 and chlorine gas. This reaction is inhibited for dilute gases.

Nitrogen trichloride can form in small amounts when public water supplies are disinfected with monochloramine, and in swimming pools by disinfecting chlorine reacting with urea in urine and sweat from bathers.

Nitrogen trichloride, trademarked as Agene, was at one time used to bleach flour, [4] but this practice was banned in the United States in 1949 due to safety concerns.


Nitrogen trichloride can irritate mucous membranes—it is a lachrymatory agent, but has never been used as such. [5] [6] The pure substance (rarely encountered) is a dangerous explosive, being sensitive to light, heat, even moderate shock, and organic compounds. Pierre Louis Dulong first prepared it in 1812, and lost two fingers and an eye in two explosions. [7] In 1813, an NCl3 explosion blinded Sir Humphry Davy temporarily, inducing him to hire Michael Faraday as a co-worker. They were both injured in another NCl3 explosion shortly thereafter. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Chlorine</span> Chemical element, symbol Cl and atomic number 17

Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.

<span class="mw-page-title-main">Sodium hypochlorite</span> Chemical compound (known in solution as bleach)

Sodium hypochlorite is an inorganic chemical compound with the formula NaOCl, comprising a sodium cation and a hypochlorite anion. It may also be viewed as the sodium salt of hypochlorous acid. The anhydrous compound is unstable and may decompose explosively. It can be crystallized as a pentahydrate NaOCl·5H
, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated.

<span class="mw-page-title-main">Nitrogen triiodide</span> Chemical compound

Nitrogen triiodide is an inorganic compound with the formula NI3. It is an extremely sensitive contact explosive: small quantities explode with a loud, sharp snap when touched even lightly, releasing a purple cloud of iodine vapor; it can even be detonated by alpha radiation. NI3 has a complex structural chemistry that is difficult to study because of the instability of the derivatives. Although nitrogen is more electronegative than iodine, the compound was so named due to its analogy to the compound nitrogen trichloride.

<span class="mw-page-title-main">Hypochlorous acid</span> Chemical compound

Hypochlorous acid is a weak acid that forms when chlorine dissolves in water, and itself partially dissociates, forming hypochlorite, ClO. HClO and ClO are oxidizers, and the primary disinfection agents of chlorine solutions. HClO cannot be isolated from these solutions due to rapid equilibration with its precursor, chlorine.

<span class="mw-page-title-main">Hypochlorite</span> Ion

In chemistry, hypochlorite is an anion with the chemical formula ClO. It combines with a number of cations to form hypochlorite salts. Common examples include sodium hypochlorite and calcium hypochlorite. The Cl-O distance in ClO is 1.69 Å.

<span class="mw-page-title-main">Phosphorus pentachloride</span> Chemical compound

Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive and moisture-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride.

<span class="mw-page-title-main">Dichlorine monoxide</span> Chemical compound

Dichlorine monoxide is an inorganic compound with the molecular formula Cl2O. It was first synthesised in 1834 by Antoine Jérôme Balard, who along with Gay-Lussac also determined its composition. In older literature it is often referred to as chlorine monoxide, which can be a source of confusion as that name now refers to the neutral species ClO.

<span class="mw-page-title-main">Borazine</span> Boron compound

Borazine, also known as borazole, is a non-polar inorganic compound with the chemical formula B3H6N3. In this cyclic compound, the three BH units and three NH units alternate. The compound is isoelectronic and isostructural with benzene. For this reason borazine is sometimes referred to as “inorganic benzene”. Like benzene, borazine is a colourless liquid with an aromatic smell.

<span class="mw-page-title-main">BCDMH</span> Chemical compound

1-Bromo-3-chloro-5,5-dimethylhydantoin is a chemical structurally related to hydantoin. It is a white crystalline compound with a slight bromine and acetone odor and is insoluble in water, but soluble in acetone.

Salt water chlorination is a process that uses dissolved salt for the chlorination of swimming pools and hot tubs. The chlorine generator uses electrolysis in the presence of dissolved salt to produce chlorine gas or its dissolved forms, hypochlorous acid and sodium hypochlorite, which are already commonly used as sanitizing agents in pools. Hydrogen is produced as byproduct too.

Monochloramine, often called chloramine, is the chemical compound with the formula NH2Cl. Together with dichloramine (NHCl2) and nitrogen trichloride (NCl3), it is one of the three chloramines of ammonia. It is a colorless liquid at its melting point of −66 °C (−87 °F), but it is usually handled as a dilute aqueous solution, in which form it is sometimes used as a disinfectant. Chloramine is too unstable to have its boiling point measured.

Chloramines refer to derivatives of ammonia and organic amines wherein one or more N-H bonds have been replaced by N-Cl bonds. Two classes of compounds are considered: inorganic chloramines and organic chloramines.

<span class="mw-page-title-main">Dichloramine</span> Chemical compound

Dichloramine is a reactive inorganic compound. It has the formula NHCl2. The yellow gas is unstable and reacts with many materials. It is formed by a reaction between ammonia and chlorine or sodium hypochlorite. It is a byproduct formed during the synthesis of monochloramine and nitrogen trichloride.

<span class="mw-page-title-main">Halazone</span> Chemical compound

Halazone is a chemical compound whose formula can be written as either C
or (HOOC)(C
. It has been widely used to disinfect drinking water.

<span class="mw-page-title-main">Chlorine-releasing compounds</span>

Chlorine-releasing compounds, also known as chlorine base compounds, is jargon to describe certain chlorine-containing substances that are used as disinfectants and bleaches. They include the following chemicals: sodium hypochlorite, chloramine, halazone, and sodium dichloroisocyanurate. They are widely used to disinfect water and medical equipment, and surface areas as well as bleaching materials such as cloth. The presence of organic matter can make them less effective as disinfectants. They come as a liquid solution, or as a powder that is mixed with water before use.

Cobalt(III) chloride or cobaltic chloride is an unstable and elusive compound of cobalt and chlorine with formula CoCl
. In this compound, the cobalt atoms have a formal charge of +3.

<span class="mw-page-title-main">Europium dichloride</span> Chemical compound

Europium dichloride is an inorganic compound with a chemical formula EuCl2. When it is irradiated by ultraviolet light, it has bright blue fluorescence.

<span class="mw-page-title-main">Vanadium(V) chloride chlorimide</span> Chemical compound

Vanadium (V) chloride chlorimide is a chemical compound containing vanadium in a +5 oxidation state bound to three chlorine atoms and with a double bond to a chlorimide group (=NCl). It has formula VNCl4. This can be also considered as a chloroiminato complex.

A chloride nitride is a mixed anion compound containing both chloride (Cl) and nitride ions (N3−). Another name is metallochloronitrides. They are a subclass of halide nitrides or pnictide halides.

Carbide chlorides are mixed anion compounds containing chloride anions and anions consisting entirely of carbon. In these compounds there is no bond between chlorine and carbon. But there is a bond between a metal and carbon. Many of these compounds are cluster compounds, in which metal atoms encase a carbon core, with chlorine atoms surrounding the cluster. The chlorine may be shared between clusters to form polymers or layers. Most carbon chloride compounds contain rare earth elements. Some are known from group 4 elements. The hexatungsten carbon cluster can be oxidised and reduced, and so have different numbers of chlorine atoms included.


  1. "Chlorine Chemistry - Chlorine Compound of the Month: Chloramines: Understanding "Pool Smell"". American Chemistry Council . Retrieved 17 December 2019.
  2. Holleman, A. F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN   978-0-12-352651-9.
  3. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  4. Hawthorn, J.; Todd, J. P. (1955). "Some effects of oxygen on the mixing of bread doughs". Journal of the Science of Food and Agriculture. 6 (9): 501–511. doi:10.1002/jsfa.2740060906.
  5. White, G. C. (1999). The Handbook of Chlorination and Alternative Disinfectants (4th ed.). Wiley. p. 322. ISBN   978-0-471-29207-4.
  6. "Health Hazard Evaluation Report: Investigation of Employee Symptoms at an Indoor Water Park" (PDF). NIOSH ENews. 6 (4). August 2008. HETA 2007-0163-3062.
  7. Thénard J. L.; Berthollet C. L. (1813). "Report on the work of Pierre Louis Dulong". Annales de Chimie et de Physique . 86 (6): 37–43.
  8. Thomas, J.M. (1991). Michael Faraday and The Royal Institution: The Genius of Man and Place (PBK). CRC Press. p. 17. ISBN   978-0-7503-0145-9.

Further reading