Nitrosyl chloride

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Nitrosyl chloride is the chemical compound NOCl. It is a yellow gas that is most commonly encountered as a decomposition product of aqua regia, a mixture of hydrochloric acid and nitric acid. The related nitrosyl halides nitrosyl fluoride, NOF, and nitrosyl bromide, NOBr, are also known.

## Contents

* 1 Structure and synthesis
* 2 Reactions
* 3 Safety
* 4 References

## Structure and synthesis

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Although its formula is written NOCl, the structure is better represented ONCl. A double bond exists between N and O (distance = 1.16 Å) and a single bond between N and Cl (distance = 1.69 Å). The O-N-Cl angle is 113°.[1]

NOCl can be prepared by the direct combination of chlorine and nitric oxide. Alternatively, nitrosylsulfuric acid and HCl also affords the compound:

HCl + NOHSO4 -> NOCl + H2SO4

It also arises from the combination of hydrochloric and nitric acids according to the following reaction:[2]

HNO3 \+ 3 HCl -> Cl2 \+ 2 H2O + NOCl

Although this mixture was used for dissolving gold for a long time the first description of the gas was done by Edmund Davy in 1831.[3]

## Reactions

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* NOCl reacts with halide acceptors to give the nitrosyl cation, [NO]+. This species is available as NOBF4.
* NOCl reacts with water to release HCl.
* Heating NOCl above 100 C gives back Cl2 and NO.
* In organic synthesis, NOCl is often employed. It adds to alkenes to afford α-chloro oximes.[4]

## Safety

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NOCl is toxic and irritating to the lungs.

## References

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1. ↑ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
2. ↑ L. J. Beckham, W. A. Fessler, M. A. Kise (1951). "Nitrosyl Chloride". Chemical Reviews. 48: 319–396. doi:10.1021/cr60151a001.CS1 maint: Multiple names: authors list (link)
3. ↑ Edmund Davy (1830 - 1837). "Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London, Vol. 3": 27–29. Unknown parameter `|titel=` ignored (`|title=` suggested) (help); Check date values in: `|year=` (help)
4. ↑ Template:OrgSynth

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