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28-660: HNC may refer to: Hydrogen isocyanide , a molecule with the formula HNC that is important to the field of astrochemistry Heptanitrocubane , an experimental high explosive Higher National Certificate , a higher education qualification in the United Kingdom High Negotiations Committee , a Syrian political-military opposition bloc headquartered in Riyadh Classical-map Hyper-Netted-Chain equation,

56-409: A good means of obtaining insight to the workings of these reactions in space. Furthermore, the study of the tautomerization of HNC to HCN (and vice versa), which has been studied extensively, has been suggested as a model by which more complicated isomerization reactions can be studied. HNC is found primarily in dense molecular clouds, though it is ubiquitous in the interstellar medium. Its abundance

84-651: A method in many-body theoretical physics for interacting uniform electron liquids in two and three dimensions Hypernetted-chain equation , a closure relation to solve the Ornstein-Zernike equation commonly applied in statistical mechanics and fluid theory Hopkins-Nanjing Center , a joint educational venture between Nanjing University and Johns Hopkins University located in Nanjing, China Habits & Contradictions , album by Schoolboy Q Huddersfield Narrow Canal , Northern England Topics referred to by

112-439: Is a commonly used tracer of dense gas in molecular clouds. Aside from the potential to use HNC to investigate gravitational collapse as the means of star formation, HNC abundance (relative to the abundance of other nitrogenous molecules) can be used to determine the evolutionary stage of protostellar cores. The HCO /HNC line ratio is used to good effect as a measure of density of gas. This information provides great insight into

140-486: Is a linear triatomic molecule with C ∞v point group symmetry . It is a zwitterion and an isomer of hydrogen cyanide (HCN). Both HNC and HCN have large, similar dipole moments , with μ HNC  = 3.05 Debye and μ HCN  = 2.98 Debye respectively. These large dipole moments facilitate the easy observation of these species in the interstellar medium . As HNC is higher in energy than HCN by 3920 cm (46.9 kJ/mol), one might assume that

168-461: Is closely linked to the abundances of other nitrogen-containing compounds. HNC is formed primarily through the dissociative recombination of HNCH and H 2 NC , and it is destroyed primarily through ion-neutral reactions with H 3 and C . Rate calculations were done at 3.16 × 10 years, which is considered early time, and at 20 K, which is a typical temperature for dense molecular clouds. These four reactions are merely

196-462: Is different from Wikidata All article disambiguation pages All disambiguation pages Hydrogen isocyanide Both hydrogen isocyanide and azanylidyniummethanide are correct IUPAC names for HNC. There is no preferred IUPAC name . The second one is according to the substitutive nomenclature rules , derived from the parent hydride azane ( NH 3 ) and the anion methanide ( CH − 3 ). Hydrogen isocyanide (HNC)

224-450: Is much higher than 10 , and is in fact on the order of unity in cold environments. This is because of the potential energy path of the tautomerization reaction; there is an activation barrier on the order of roughly 12,000 cm for the tautomerization to occur, which corresponds to a temperature at which HNC would already have been destroyed by neutral-neutral reactions. In practice, HNC is almost exclusively observed astronomically using

252-450: Is relatively straightforward, which is a major motivation for its research. Its J = 1→0 transition occurs in a clear portion of the atmospheric window, and it has numerous isotopomers that are easily studied. Additionally, its large dipole moment makes observations particularly simple. Moreover, HNC is a fundamentally simple molecule in its molecular nature. This makes the study of the reaction pathways that lead to its formation and destruction

280-530: Is the region of the radio spectrum that penetrate the Earth's atmosphere . Typically, the lower limit of the radio window's range has a value of about 10 MHz (λ ≈ 30 m); the best upper limit achievable from optimal terrestrial observation sites is equal to approximately 1 THz (λ ≈ 0.3 mm). It plays an important role in astronomy; up until the 1940s, astronomers could only use the visible and near infrared spectra for their measurements and observations. With

308-560: The IRAM 30-m telescope at the Pico de Veleta in Spain. It was observed via its J = 1→0 transition at 90.7 GHz toward IC 342. A number of detections have been made towards the end of confirming the temperature dependence of the abundance ratio of [HNC]/[HCN]. A strong fit between temperature and the abundance ratio would allow observers to spectroscopically detect the ratio and then extrapolate

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336-401: The J  = 1→0 transition. This transition occurs at ~90.66 GHz, which is a point of good visibility in the atmospheric window , thus making astronomical observations of HNC particularly simple. Many other related species (including HCN) are observed in roughly the same window. HNC is intricately linked to the formation and destruction of numerous other molecules of importance in

364-571: The solar activity and the geographic position. When performing observations, radio astronomers try to extend the upper limit of the radio window towards the 1 THz optimum, since the astronomical objects give spectral lines of greater intensity in the higher frequency range. Tropospheric water vapour greatly affects the upper limit since its resonant absorption frequency bands are 22.3 GHz (λ ≈ 1.32 cm), 183.3 GHz (λ ≈ 1.64 mm) and 323.8 GHz (λ ≈ 0.93 mm). The tropospheric oxygen's bands at 60 GHz (λ ≈ 5.00 mm) and 118.74 GHz (λ ≈ 2.52 mm) also affect

392-509: The National Radio Astronomy Observatory. The main molecular isotope, H C N, was observed via its J = 1→0 transition at 88.6 GHz in six different sources: W3 (OH), Orion A, Sgr A(NH3A), W49, W51, DR 21(OH). A secondary molecular isotope, H C N, was observed via its J = 1→0 transition at 86.3 GHz in only two of these sources: Orion A and Sgr A(NH3A). HNC was then later detected extragalactically in 1988 using

420-472: The abundance of HCN, and the two tend to exist in a specific ratio based on the environment. This is because the reactions that form HNC can often also form HCN, and vice versa, depending on the conditions in which the reaction occurs, and also that there exist isomerization reactions for the two species. HCN (not HNC) was first detected in June 1970 by L. E. Snyder and D. Buhl using the 36-foot radio telescope of

448-524: The development of radio telescopes , the radio window became more and more utilizable, leading to the development of radio astronomy that provided astrophysicists with valuable observational data. The lower and upper limits of the radio window's range of frequencies are not fixed; they depend on a variety of factors. The upper limit is affected by the vibrational transitions of atmospheric molecules such as oxygen (O 2 ), carbon dioxide (CO 2 ), and water (H 2 O), whose energies are comparable to

476-430: The electron density in electrons per cubic meter. Since it is highly dependent on sunlight, the value of N e {\displaystyle N_{e}} changes significantly from daytime to nighttime usually being lower during the day, leading to a decrease of the radio window's lower limit and higher during the night, causing an increase of the radio window's lower frequency end. However, this also depends on

504-408: The energies of mid-infrared photons : these molecules largely absorb the mid-infrared radiation that heads towards Earth. The radio window's lower frequency limit is greatly affected by the ionospheric refraction of the radio waves whose frequencies are approximately below 30 MHz (λ > 10 m); radio waves with frequencies below the limit of 10 MHz (λ > 30 m) are reflected back into space by

532-473: The four most dominant, and thus the most significant in the formation of the HNC abundances in dense molecular clouds; there are dozens more reactions for the formation and destruction of HNC. Though these reactions primarily lead to various protonated species, HNC is linked closely to the abundances of many other nitrogen containing molecules, for example, NH 3 and CN. The abundance HNC is also inexorably linked to

560-504: The interstellar medium. In 1997, HNC was observed along the TMC-1 ridge and its abundance relative to HCO was found to be constant along the ridge—this led credence to the reaction pathway that posits that HNC is derived initially from HCO . One significant astronomical detection that demonstrated the practical use of observing HNC occurred in 2006, when abundances of various nitrogenous compounds (including HN C and H NC) were used to determine

588-454: The interstellar medium—aside from the obvious partners HCN, protonated hydrogen cyanide (HCNH ) , and cyanide (CN) , HNC is linked to the abundances of many other compounds, either directly or through a few degrees of separation. As such, an understanding of the chemistry of HNC leads to an understanding of countless other species—HNC is an integral piece in the complex puzzle representing interstellar chemistry. Furthermore, HNC (alongside HCN)

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616-470: The ionosphere. The lower limit is proportional to the density of the ionosphere's free electrons and coincides with the plasma frequency : f p = 9 N e , {\displaystyle f_{p}=9{\sqrt {N_{e}}},} where f p {\displaystyle f_{p}} is the plasma frequency in Hz and N e {\displaystyle N_{e}}

644-478: The mechanisms of the formation of (Ultra-)Luminous Infrared Galaxies ((U)LIRGs), as it provides data on the nuclear environment, star formation , and even black hole fueling. Furthermore, the HNC/HCN line ratio is used to distinguish between photodissociation regions and X-ray-dissociation regions on the basis that [HNC]/[HCN] is roughly unity in the former, but greater than unity in the latter. The study of HNC

672-402: The same term [REDACTED] This disambiguation page lists articles associated with the title HNC . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=HNC&oldid=850638860 " Category : Disambiguation pages Hidden categories: Short description

700-536: The stage of evolution of the protostellar core Cha-MMS1 based on the relative magnitudes of the abundances. On 11 August 2014, astronomers released studies, using the Atacama Large Millimeter/Submillimeter Array (ALMA) for the first time, that detailed the distribution of HCN , HNC, H 2 CO , and dust inside the comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON) . Radio window The radio window

728-458: The temperature of the environment, thus gaining great insight into the environment of the species. The abundance ratio of rare isotopes of HNC and HCN along the OMC-1 varies by more than an order of magnitude in warm regions versus cold regions. In 1992, the abundances of HNC, HCN, and deuterated analogs along the OMC-1 ridge and core were measured and the temperature dependence of the abundance ratio

756-514: The two would have an equilibrium ratio ( [ H N C ] [ H C N ] ) e q {\textstyle \left({\frac {[HNC]}{[HCN]}}\right)_{eq}} at temperatures below 100 Kelvin of 10 . However, observations show a very different conclusion; ( [ H N C ] [ H C N ] ) o b s e r v e d {\textstyle \left({\frac {[HNC]}{[HCN]}}\right)_{observed}}

784-403: Was confirmed. A survey of the W 3 Giant Molecular Cloud in 1997 showed over 24 different molecular isotopes, comprising over 14 distinct chemical species, including HNC, HN C, and H NC. This survey further confirmed the temperature dependence of the abundance ratio, [HNC]/[HCN], this time even confirming the dependence of the isotopomers. These are not the only detections of importance of HNC in

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