The methylene amidogen radical (H₂CN) was discovered in TMC-1 using the 12m telescope at Kitt Peak by Ohishi and co-workers and reported in 1994. The tentative detection of H₂CN in Sgr B2(N) was also noted. The only additional observation to date was the tentative assignment of one line of H₂CN in the R2 region of Monoceros made by Ginard et al. in 2012. The laboratory rotational spectrum of methylene amidogen was measured by Yamamoto & Saito in 1992.

The methylene amidogen radical is formed when a N atom is coupled to the triplet ground state of CH2 as shown in the coupling diagram to the right. σ and π bonds are formed, leaving a singly-occupied orbital on N that is in the plane of the molecule as shown in the second figure.