Iron monocyanide (FeCN) was detected in IRC +10216 by Zack et al. and reported in 2011. The 12 m telescope at the Arizona Radio Observatory was used to make the observations. There has been some debate about the ground state of FeCN, which stems from the fact that there are multiple quartet and sextet states with similar energies. The experimental study of Flory & Ziurys found the ground state to be a quartet, while theoretical studies such as those by DeYonker et al. and Hirano et al. find that the sextet state is more stable.

A number of other cyanide species have been observed in interstellar or circumstellar media, including hydrogen cyanide, methyl cyanide, vinyl cyanide, cyanimide, ethyl cyanide, cyano methyl radical, sodium cyanide, magnesium cyanide, silicon cyanide, cyanoallene, cyanoformaldehyde, amino acetonitrile, n-propyl cyanide, and potassium cyanide.