Cyano radical

Cyano radical
Preferred IUPAC name Cyano radical
Systematic name Isocyano
Other names Cyanyl Nitrile
Identifiers
CAS number	2074-87-5 Y
PubChem	5359238
ChemSpider	4514240 Y
ChEBI	CHEBI:293​06 N
Beilstein Reference	1697323
Gmelin Reference	88
Jmol-3D images	Image 1 Image 2
SMILES [C]#N [C]#N
InChI InChI=1S/CN/c1-2 Y Key: JEVCWSUVFOYBFI-UHFFFAOYSA-N Y
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

The cyano radical is a radical with molecular formula ·CN. The cyano radical was one of the first detected molecules in the interstellar medium and has helped the field of astrochemistry a great deal. The first discovery was performed with a coude spectrograph which was made famous and credible due to this detection. ·CN has been observed in both diffuse clouds and dense clouds.^[1] Usually, CN is detected in regions with hydrogen cyanide, hydrogen isocyanide, and HCHN⁺ since it is also used In the creation and destruction of these molecules.

Physical Properties

The cyano radical exists as a resonance structure, the form depicted with the unpaired electron on the carbon, is in fact a minor contributor, the major contributor is the isocyano radical. In the isocyano radical, the electron is associated with the nitrogen, resulting in a charge separation similar to carbon monoxide.

·CN has a radical on the carbon and a dipole moment of 1.45 Debye. ·CN has a ²Σ ground electronic state. The selection rules are:

N + S = J

J + I = F

Where N is the angular momentum, S is the electric spin, and I is the nitrogen nuclear spin, which is always 1.^[2]

Formation and destruction of ·CN

Formation

• Dissociative Recombination In Diffuse Clouds: HCN⁺ + e^- → ·CN + ·H ^[1]

• Photo-Dissociation In Dense Clouds: HCN + hv → ·CN + ·H^[3]

Destruction

H₃ + ·CN → HCN⁺ + H₂

Detections of ·CN

·CN was first detected In 1941 by A. McKellar In the interstellar medium.^[3]

The coude spectrograph and a 100-inch (2.5 m) telescope were used to observe ·CN's interstellar lines and ultraviolet spectra. Use of the spectrograph proved McKellar's findings to Be correct and also made the spectrograph famous.^[4] In 1970, ·CN's first rotational transition from J=0 to J=1 was detected In the Orion Nebula and W₅₁.^[5] The first detection of ·CN in extragalactic sources were seen toward Sculptor Galaxy (NGC 253), IC 342, and M82 In 1988. These emission lines seen were from N=1 to N=0 and N=2 to N=1.^[6] In 1991, the ·CN vibration-rotational bands were observed in a king furnace at the National Solar Observatory using a McMath Fourier-Transform spectrometer. The observed 2 to 0 lines show an extreme hyperfine structure.^[7] In 1995, the rotational absorption spectrum of ·CN in the ground state was observed in the 1 THz region, and most of the lines were measured in the range of 560 to 1020 GHz. Four new rotational transitions were measured; N=8 to N=8, J=15/2 to J=17/2 and J=17/2 to J=19/2; N=7 to N=8, J=15/2 to J=17/2 and J=13/2 to J=15/2.^[8]

References

1. ^ ^{a b} Liszt, H.; Lucas, R. (2001). "Comparative chemistry of difuse clouds" (PDF). Astronomy and Astrophysics (Astronomy and Astrophysics) 370 (2): 1–11. Bibcode 2001A&A...370..576L. doi:10.1051/0004-6361:20010260. http://www.aanda.org/index.php?option=article&access=bibcode&bibcode=2001A%2526A...370..576LPDF. Retrieved 4 August 2009. 
2. ^ Skatrud, David D.; De Lucia, Frank C.; Blake, Geoffrey A.; Sastry, K. V. L. N. (1983). "The millimeter and submillimeter spectrum of ·CN in its first four vibrational states". Journal of Molecular Spectroscopy 99 (1): 35–46. doi:10.1016/0022-2852(83)90290-4. 
3. ^ ^{a b} Bakker, Eric J.; Waters, L.B.F.M.; Lamers, Henny J.G.L.M.; Trams, Norman R.; Van der Wolf, Frank L.A. (23 October 1995) (PDF). Detection of C2, CN, and NaID absorption in the AGB remnant of HD56126. Astronomy and Astrophysics. arXiv:/9510122v1 astro-ph /9510122v1. 
4. ^ McKellar, Andrew (June 1940). "Evidence for the Molecular Origin of Some Hitherto Unidentified Interstellar Lines". Publications of the Astronomical Society of the Pacific (Publications of the Astronomical Society of the Pacific) 52 (307): 187. Bibcode 1940PASP...52..187M. doi:10.1086/125159. 
5. ^ Walter S., Adams (January 1941). "Some Results with the COUDÉ Spectrograph of the Mount Wilson Observatory.". The Astrophysical Journal (Astrophysical Journal) 93: 11. Bibcode 1941ApJ....93...11A. doi:10.1086/144237. 
6. ^ Henkel, C.; Schilke, P.; Mauersberger, R. (July 1988). Molecules in external galaxies - The detection of CN, C2H, and HNC, and the tentative detection of HC3N. 201. Astronomy and Astrophysics. pp. L23–L26. Bibcode 1988A&A...201L..23H. 
7. ^ Jefferts, K. B.; Penzias, A. A.; Wilson, R. W. (August 1970). "Observation of the CN Radical in the Orion Nebula and W51". The Astrophysical Journal (Astrophysical Journal) 161: L87. Bibcode 1970ApJ...161L..87J. doi:10.1086/180576. 
8. ^ Klisch, E.; Klaus, T.; Belov, S. P.; Winnewisser, G.; Herbst, E. (December 1995). Laboratory rotational spectrum of CN in the 1 THz region.. 304. Astronomy and Astrophysics. pp. L5. Bibcode 1995A&A...304L...5K.