Nitrogen trichloride
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| |
| Names | |
|---|---|
| Other names
Trichloramine
Agene Nitrogen(III) chloride Trichloroazane Trichlorine nitride | |
| Identifiers | |
| ECHA InfoCard | 100.030.029 |
| RTECS number |
|
CompTox Dashboard (EPA)
|
|
| Properties | |
| Molar mass | 120.365 g/mol |
| Appearance | yellow oily liquid |
| Density | 1.635 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 | |
| rhombohedral (below -40 °C) | |
| trigonal pyramidal | |
| 0.6 D | |
| Thermochemistry | |
Std molar
entropy (S⦵298) |
? J.K−1.mol−1 |
Std enthalpy of
formation (ΔfH⦵298) |
+232 kJ/mol |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other anions
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Nitrogen trifluoride Nitrogen tribromide Nitrogen triiodide |
Other cations
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Phosphorus trichloride Arsenic trichloride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Nitrogen trichloride, also known as trichloramine, trichlorine nitride (wrong in nomenclature of binary compounds; Nitrogen trichloride is a sound name following the rules of systematic nomenclature) 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 between disinfecting chlorine and urea in urine from bathers).
In pure form, NCl3 is highly reactive. Nitrogen trichloride can form in small amounts when public water supplies are disinfected with monochloramine, and at given levels it can irritate mucous membranes.[1] Nitrogen trichloride was trademarked as Agene and used to artificially bleach and age flour. It has the same effect as that of tear gas, but has never been used as such.[2]
Preparation and structure
The compound is prepared by treatment of ammonium salts, such as ammonium nitrate with chlorine:
- 4 NH3 + 3 Cl2 → NCl3 + 3 NH4Cl
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°.[3] The Pauling electronegativities are very similar for nitrogen (3.04) and chlorine (3.16).
Reactions
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. Most of its reactivity is consistent with this description.
Nitrogen trichloride is hydrolyzed by hot water to release ammonia and hypochlorous acid.
- NCl3 + 3 H2O → NH3 + 3 HOCl
Safety
Nitrogen trichloride is a dangerous explosive, being sensitive to light, heat, and organic compounds. Pierre Louis Dulong first prepared it in 1812, and lost two fingers and an eye in two separate explosions. An explosion from NCl3 blinded Sir Humphry Davy temporarily, inducing him to hire Michael Faraday as a co-worker. Belgian researchers reported a possible link between NCl3 and rising numbers of childhood asthma cases, in what they call the pool chlorine hypothesis, as an alternative to the hygiene hypothesis with a closer causal link.[4]
References
- ^ National Institute for Occupational Safety and Health. (2008, August). NIOSH eNews, 6(4). Retrieved August 27, 2008, from http://www.cdc.gov/niosh/enews/enewsV6N4.html
- ^ George Clifford White: The handbook of chlorination and alternative disinfectants. 4th Edition, Wiley, 1999, ISBN 9780471292074, p. 322
- ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- ^
Bernard A, Carbonnelle S, de Burbure C, Michel O, Nickmilder M (2006). "Chlorinated pool attendance, atopy, and the risk of asthma during childhood" (PDF). Environmental Health Perspectives. 114 (10): 1567–1573. doi:10.1289/ehp.8461. PMC 1626429. PMID 17035144.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
Further reading
- Jander, J. (1976). Adv. Inorg. Chem. Radiochem. 19: 2.
- P. Kovacic, M. K. Lowery, K. W. Field (1970). "Chemistry of N-bromamines and N-chloramines". Chemical Reviews. 70 (6): 639. doi:10.1021/cr60268a002.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Hartl, H.;, Schoner, J.; Jander, J.; Schulz, H. (1975). "Structure of Solide Nitrogen-Trichloride (-125°C)". Zeitschrift für Anorganische und Allgemeine Chemie. 413 (1): 61–71. doi:10.1002/zaac.19754130108.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Cazzoli, G.; Favero, P. G.; Dalborgo, A. (1974). "Molecular-Structure, Nuclear-Quadruple Coupling-Constant and Dipole-Moment of Nitrogen Trichloride from Microwave Spectroscopy". Journal of Molecular Spectroscopy. 50 (1–3): 82. doi:10.1016/0022-2852(74)90219-7.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Bayersdo, L.; Engelhar, U., Fischer, J.; Hohne, K.; Jander, J. (1969). "Nitrogen-chlorine compounds: Infrared spectra and Raman spectra of nitrogen trichloride". Zeitschrift für anorganische und allgemeine Chemie. 366 (3–4): 169-. doi:10.1002/zaac.19693660308.
{{cite journal}}: CS1 maint: multiple names: authors list (link)