The second one is according to the substitutive nomenclature rules, derived from the parent hydride azane (NH3) and the anion methanide (CH−3).

[1] Hydrogen isocyanide (HNC) is a linear triatomic molecule with C∞v point group symmetry.

[3] These large dipole moments facilitate the easy observation of these species in the interstellar medium.

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.

[6][7] HNC is intricately linked to the formation and destruction of numerous other molecules of importance in 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.

Furthermore, HNC (alongside HCN) is a commonly used tracer of dense gas in molecular clouds.

Its J = 1→0 transition occurs in a clear portion of the atmospheric window, and it has numerous isotopomers that are easily studied.

[5][9][10] HNC is found primarily in dense molecular clouds, though it is ubiquitous in the interstellar medium.

[12][13] Rate calculations were done at 3.16 × 105 years, which is considered early time, and at 20 K, which is a typical temperature for dense molecular clouds.

Though these reactions primarily lead to various protonated species, HNC is linked closely to the abundances of many other nitrogen containing molecules, for example, NH3 and CN.

[16] The main molecular isotope, H12C14N, 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).

HNC was then later detected extragalactically in 1988 using the IRAM 30-m telescope at the Pico de Veleta in Spain.

A number of detections have been made towards the end of confirming the temperature dependence of the abundance ratio of [HNC]/[HCN].

[3] 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, H2CO, and dust inside the comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON).