Nitrogen trichloride

Nitrogen trichloride
Names
Other names
Trichloramine
Agene
Nitrogen(III) chloride
Trichloroazane
Trichlorine nitride
Identifiers
10025-85-1 N
ChEBI CHEBI:37382 YesY
ChemSpider 55361 YesY
EC Number 233-045-1
Jmol interactive 3D Image
PubChem 61437
RTECS number QW974000
Properties
Cl3N
Molar mass 120.36 g·mol−1
Appearance yellow 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)
immiscible
slowly decomposes
Solubility soluble in benzene, chloroform, CCl4, CS2, PCl3
Structure
orthorhombic (below −40 °C)
trigonal pyramidal
0.6 D
Thermochemistry
232 kJ/mol
Hazards
not listed
NFPA 704
93 °C (199 °F; 366 K)
Related compounds
Other anions
Nitrogen trifluoride
Nitrogen tribromide
Nitrogen triiodide
Other cations
Phosphorus trichloride
Arsenic trichloride
Related chloramines
Chloramine
Dichloramine
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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Infobox references

Nitrogen trichloride, also known as trichloramine, is the chemical compound with the formula NCl3. This yellow, oily, pungent-smelling liquid is most commonly encountered as a byproduct of chemical reactions between ammonia-derivatives and chlorine (for example, in swimming pools).

Preparation and structure

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

Intermediates in this conversion include chloramine 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°.[1]

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 used to artificially bleach and age flour, but was banned in 1949: In humans Agene was found to cause severe and widespread neurological disorders leading to its banning in 1947. Dogs that ate bread made from treated flour suffered epileptic-like fits; the toxic agent was methionine sulfoximine.[2]

Reactions

Despite the similarities of the Pauling electronegativities of nitrogen and chlorine, this molecule has moderate polarity with negative charges residing on Chlorine. So the nitrogen in NCl3 is often considered to have the +3 oxidation state and the chlorine atoms are considered to be in the -1 oxidation state.
It is hydrolyzed by hot water to release ammonia and hypochlorous acid.

NCl3 + 3 H2O NH3 + 3 HOCl

Safety

Nitrogen trichloride can irritate mucous membranes—it is a lachrymatory agent, but has never been used as such.[3][4] 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. 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.[5]

See also

References

  1. Holleman, A. F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 0-12-352651-5.
  2. Shaw, CA; Bains, JS (1998). "Did consumption of flour bleached by the agene process contribute to the incidence of neurological disease?". Medical Hypotheses 51 (6): 477–81. doi:10.1016/S0306-9877(98)90067-6. PMID 10052866.
  3. White, G. C. (1999). The Handbook of Chlorination and Alternative Disinfectants (4th ed.). Wiley. p. 322. ISBN 978-0-471-29207-4.
  4. "Health Hazard Evaluation Report: Investigation of Employee Symptoms at an Indoor Water Park" (pdf). NIOSH eNews (National Institute for Occupational Safety and Health) 6 (4). August 2008. HETA 2007-0163-3062.
  5. 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

External links

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